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Topic Review
Empire of Liberty
The Empire of Liberty is a theme developed first by Thomas Jefferson to identify the responsibility of the United States to spread freedom across the world. Jefferson saw the mission of the U.S. in terms of setting an example, expansion into western North America, and by intervention abroad. Major exponents of the theme have been James Monroe (and his Monroe Doctrine), Andrew Jackson and James K. Polk (who promoted Manifest Destiny), Abraham Lincoln (in the Gettysburg Address), Theodore Roosevelt, Woodrow Wilson (and "Wilsonianism"), Franklin D. Roosevelt, Harry Truman, Ronald Reagan, Bill Clinton, and George W. Bush. In the history of U.S. foreign policy, the Empire of Liberty has provided motivation to fight the Spanish–American War (1898), World War I (1917-18), the later part of World War II (1941-45), the Cold War (1947–91) and the War on Terror (2001–present).
  • 6.1K
  • 26 Oct 2022
Topic Review
Solar Reflectance Measurement
The relative amount of solar radiation reflected by a surface is specified as solar reflectance, or albedo. The latter term sometimes refers only to visible sunlight (Vis), while the former generally refers to the entire spectrum of solar radiation, including near-infrared (NIR) and ultraviolet (UV) radiation. However, the scientific and technical communities consider albedo and solar reflectance synonymous, with both referring to the entire solar spectrum. Solar reflectance is usually expressed as a value between zero, for a surface absorbing all incoming radiation, and one, for a perfect reflector—or as a percentage between 0 and 100%. For an opaque surface, solar reflectance is complementary to solar absorptance—that is, the ratio of absorbed to total incident solar energy. Several instruments are available for its measurement, in the laboratory on in situ, according to several standard test methods.
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  • 23 Nov 2021
Topic Review
Synthesis of Monoterpene Thiols
Thiols are one of the most convenient synthons in the synthesis of organosulfur compounds. The typical methods to prepare monoterpene thiols include the electrophilic addition of H2S or dithiols to the double bond of monoterpenes; nucleophilic substitution of halides; tosylates/mesylates obtained from corresponding monoterpene alcohols; thia-Michael addition of S-nucleophiles to α,β-unsaturated ketones; nucleophilic epoxide ring opening; nucleophilic substitution of the activated methylene protons; and reduction of sulfochlorides, dithiolanes, thiiranes, and sultones.
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  • 07 Nov 2023
Topic Review
Maitum Anthropomorphic Pottery
In 1991, the National Museum archaeological team discovered anthropomorphic secondary burial jars in Ayub Cave, Barangay Pinol, Maitum, Sarangani Province, Mindanao, Philippines. The jars are commonly known today as Maitum jars. They are made of earthenware, and are characterized by their design that suggests human figures with complete or partial facial features of the first inhabitants in Mindanao. Furthermore, they give emphasis to the Filipinos’ popular belief of life after death. According to Dr. Eusebio Dizon, head of the archaeological team, this type of burial jars are “remarkably unique and intriguing” because they have not been found elsewhere in Southeast Asia. Thus, many archaeologists from Vietnam, Thailand, Malaysia, Laos, Cambodia, Burma and Indonesia gained interest on this initial find and a number of archaeological - either government or privately sponsored - excavations have been conducted to recover these artifacts. These jars have characteristics that belong to the Developed Metal Age Period in the Philippines [calibrated date of 190 BC to 500 AD]. According to the laboratory results determined through radiocarbon dating, these secondary burial jars date back to the Metal Age. Two conventional dates were 1830 +/-60 B.P. [calibrated date of AD 70 to 370] and 1920 +/- 50 B.P. [calibrated date of 5 BC to 225 AD]. Experts used soot samples taken from the walls of a small earthenware vessel found inside one of the larger burial jars.
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  • 12 Oct 2022
Topic Review
Adhan
The adhan, athan, or azaan (Arabic: أَذَان [ʔaˈðaːn]) (also called in Turkish: Ezan) is the Islamic call to worship, recited by the muezzin at prescribed times of the day. The root of the word is ʾadhina أَذِنَ meaning "to listen, to hear, be informed about". Another derivative of this word is ʾudhun (أُذُن), meaning "ear". Adhan is called out by a muezzin from the mosque five times a day, traditionally from the minaret, summoning Muslims for mandatory (fard) worship (salat). A second call, known as iqama, (set up) then summons Muslims to line up for the beginning of the prayers. The main purpose behind the multiple loud pronouncements of adhan in every mosque is to make available to everyone an easily intelligible summary of Islamic belief. In modern times, loudspeakers have been installed on minarets for this purpose. The adhan recites the Takbir (God is great) followed by the Shahada (There is no god but God, Muhammad is the messenger of God). This statement of faith, called the Kalimah, is the first of the Five Pillars of Islam.
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  • 14 Oct 2022
Topic Review
Fear, Uncertainty and Doubt
Fear, uncertainty and doubt (often shortened to FUD) is a disinformation strategy used in sales, marketing, public relations, politics, cults, and propaganda. FUD is generally a strategy to influence perception by disseminating negative and dubious or false information and a manifestation of the appeal to fear. While the phrase dates to at least the early 20th century, the present common usage of disinformation related to software, hardware and technology industries generally appeared in the 1970s to describe disinformation in the computer hardware industry, and has since been used more broadly.
  • 6.1K
  • 20 Oct 2022
Topic Review
French Geodesic Mission
The French Geodesic Mission (also called the Geodesic Mission to Peru, Geodesic Mission to the Equator and the Spanish-French Geodesic Mission) was an 18th-century expedition to what is now Ecuador carried out for the purpose of measuring the roundness of the Earth and measuring the length of a degree of latitude at the Equator. The mission was one of the first geodesic (or geodetic) missions carried out under modern scientific principles, and the first major international scientific expedition.
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  • 19 Oct 2022
Topic Review
Electronic Skin
Mimicking skin sensorial properties, the development of “electronic skin” (e-skin) holds the promise of developing medical monitoring and highly sensitive prosthetic devices, biocompatible compliant medical implants, enhanced robotics, and more. The e-skin-related research field is a robust interdisciplinary approach, which combines micro-/nanoelectronics, material science, biotechnology, data transmission, and data processing technologies. The potential of epidermal electronics as biomimetic sensors, soft neural probes, prosthetics, implantable biomedical electronics, robotics, and a whole range of other skin-inspired devices show great potential to change the world. Its feasibility, however, relies on the desired e-skin characteristics such as flexibility, stretchability, self-healing ability, self-powering, biocompatibility, biodegradability and last, but not least, the reliability of large-scale manufacturing processes. 
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  • 18 Oct 2021
Topic Review
Transactinide Element
In chemistry, transactinide elements (also, transactinides, or super-heavy elements) are the chemical elements with atomic numbers from 104 to 120. Their atomic numbers are immediately greater than those of the actinides, the heaviest of which is lawrencium (atomic number 103). Glenn T. Seaborg first proposed the actinide concept, which led to the acceptance of the actinide series. He also proposed the transactinide series ranging from element 104 to 121 and the superactinide series approximately spanning elements 122 to 153. The transactinide seaborgium was named in his honor. By definition, transactinide elements are also transuranic elements, i.e. have an atomic number greater than uranium (92). The transactinide elements all have electrons in the 6d subshell in their ground state. Except for rutherfordium and dubnium, even the longest-lasting isotopes of transactinide elements have extremely short half-lives, measured in seconds, or smaller units. The element naming controversy involved the first five or six transactinide elements. These elements thus used systematic names for many years after their discovery had been confirmed. (Usually the systematic names are replaced with permanent names proposed by the discoverers relatively shortly after a discovery has been confirmed.) Transactinides are radioactive and have only been obtained synthetically in laboratories. None of these elements has ever been collected in a macroscopic sample. Transactinide elements are all named after physicists and chemists or important locations involved in the synthesis of the elements. IUPAC defines an element to exist if its lifetime is longer than 10−14 seconds, which is the time it takes for the nucleus to form an electron cloud.
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  • 01 Dec 2022
Topic Review
Silappatikaram
Silappatikāram (Tamil: சிலப்பதிகாரம், IPA: ʧiləppət̪ikɑːrəm, lit. "the Tale of an Anklet"), also referred to as Silappathikaram or Silappatikaram, is the earliest Hindu-Jain Tamil semi-legendary epic. It is a poem of 5,730 lines in almost entirely akaval (aciriyam) meter. The epic is a tragic love story of an ordinary couple, Kannaki and her husband Kovalan. The Silappathikaram has more ancient roots in the Tamil bardic tradition, as Kannaki and other characters of the story are mentioned or alluded to in the Sangam literature such as in the Naṟṟiṇai and later texts such as the Kovalam Katai. It is attributed to a prince-turned-monk Iḷaṅkõ Aṭikaḷ, and was probably composed in the 5th or 6th century CE. The Silappatikaram is set in a flourishing seaport city of the early Chola kingdom. Kannaki and Kovalan are a newly married couple, in love, and living in bliss. Over time, Kovalan meets Matavi (Madhavi) – a courtesan. He falls for her, leaves Kannaki and moves in with Matavi. He spends lavishly on her. Kannaki is heartbroken, but as the chaste woman, she waits despite her husband's unfaithfulness. During the festival for Indra, the rain god, there is a singing competition. Kovalan sings a poem about a woman who hurt her lover. Matavi then sings a song about a man who betrayed his lover. Each interprets the song as a message to the other. Kovalan feels Matavi is unfaithful to him, and leaves her. Kannaki is still waiting for him. She takes him back. Kannagi and Kovalan leave the city and travel to Madurai of the Pandya kingdom. Kovalan is penniless and destitute. He confesses his mistakes to Kannagi. She forgives him and tells him the pain his unfaithfulness gave her. Then she encourages her husband to rebuild their life together and gives him one of her jeweled anklets to sell to raise starting capital. Kovalan sells it to a merchant, but the merchant falsely frames him as having stolen the anklet from the queen. The king arrests Kovalan and then executes him, without the due checks and processes of justice. When Kovalan does not return home, Kannagi goes searching for him. She learns what has happened. She protests the injustice and then proves Kovalan's innocence by throwing in the court the other jeweled anklet of the pair. The king accepts his mistake. Kannagi curses the king and curses the people of Madurai, tearing off her breast and throwing it at the gathered public. The king dies. The society that had made her suffer, suffers in retribution as the city of Madurai is burnt to the ground because of her curse. In the third section of the epic, gods and goddesses meet Kannagi and she goes to heaven with god Indra. The royal family of the Chera kingdom learns about her, resolves to build a temple with Kannagi as the featured goddess. They go to the Himalayas, bring a stone, carve her image, call her goddess Pattini, dedicate a temple, order daily prayers, and perform a royal sacrifice. The Silappathikaram is an ancient literary Jain masterpiece. It is to the Tamil culture what the Iliad is to the Greek culture, states R. Parthasarathy. It blends the themes, mythologies and theological values found in the Jain, Buddhist and Hindu religious traditions. It is a Tamil story of love and rejection, happiness and pain, good and evil like all classic epics of the world. Yet unlike other epics that deal with kings and armies caught up with universal questions and existential wars, the Silappathikaram is an epic about an ordinary couple caught up with universal questions and internal, emotional war. The Silappathikaram legend has been a part of the Tamil oral tradition. The palm-leaf manuscripts of the original epic poem, along with those of the Sangam literature, were rediscovered in monasteries in the second half of the 19th century by UV Swaminatha Aiyar – a pandit and Tamil scholar. After being preserved and copied in temples and monasteries in the form of palm-leaf manuscripts, Aiyar published its first partial edition on paper in 1872, the full edition in 1892. Since then the epic poem has been translated into many languages including English.
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  • 08 Oct 2022
Topic Review
Roadside Unit Deployment in Internet of Vehicles Systems
The network technology known as Internet of Vehicles (IoV) has been developed to improve road safety and vehicle security, with the goal of servicing the digital demands of car drivers and passengers. The highly dynamical network topology that characterizes these networks, and which often leads to discontinuous transmissions, is one of the most significant challenges of IoV. To address this issue, IoV infrastructure-based components known as roadside units (RSU) are designed to play a critical role by providing continuous transmission coverage and permanent connectivity. The main challenges that arise when deploying RSUs are balancing IoVs’ performances and total cost so that optimal vehicle service coverage is provided with respect to some target Quality of Service (QoS) such as: service coverage, throughput, low latency, or energy consumption.
  • 6.1K
  • 05 May 2022
Topic Review
Post-Study System Usability Questionnaire
The Post-Study System Usability Questionnaire (PSSUQ) is an evaluation tool used to assess perceived usability, and it does not require a license for its usage. As PSSUQ is a common and widely used usability tool it has been translated into many languages, mainly European.
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  • 20 Sep 2023
Topic Review
Style (Sociolinguistics)
In sociolinguistics, a style is a set of linguistic variants with specific social meanings. In this context, social meanings can include group membership, personal attributes, or beliefs. Linguistic variation is at the heart of the concept of linguistic style—without variation there is no basis for distinguishing social meanings. Variation can occur syntactically, lexically, and phonologically. Many approaches to interpreting and defining style incorporate the concepts of indexicality, indexical order, stance-taking, and linguistic ideology. Note that a style is not a fixed attribute of a speaker. Rather, a speaker may use different styles depending on context. Additionally, speakers often incorporate elements of multiple styles into their speech, either consciously or subconsciously, thereby creating a new style.
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  • 22 Nov 2022
Topic Review
Columbia Business School
Columbia Business School (CBS) is the business school of Columbia University in the City of New York in Manhattan, New York City . Established in 1916, Columbia Business School is one of the oldest business schools in the world. It is one of six Ivy League business schools, and is among the most selective of top business schools.
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  • 11 Oct 2022
Topic Review
Thorium-Based Nuclear Power
Thorium-based nuclear power generation is fueled primarily by the nuclear fission of the isotope uranium-233 produced from the fertile element thorium. A thorium fuel cycle can offer several potential advantages over a uranium fuel cycle [Note 1] —including much greater abundance of thorium found on Earth, superior physical and nuclear fuel properties, and reduced nuclear waste production. One advantage of thorium fuel is its low weaponization potential; it is difficult to weaponize the uranium-233/232 and plutonium-238 isotopes largely consumed in thorium reactors. Between 1999 and , the number of operational thorium reactors in the world has risen from zero, to a handful of research reactors, to commercial plans for producing full-scale thorium-based reactors for use as power plants on a national scale. Some believe thorium is key to developing a new generation of cleaner, safer nuclear power. In 2011 a group of scientists at the Georgia Institute of Technology assessed thorium-based power as "a 1000+ year solution or a quality low-carbon bridge to truly sustainable energy sources solving a huge portion of mankind’s negative environmental impact." However, development of thorium power has significant start-up costs. Development of breeder reactors in general (including thorium reactors, which are breeders by nature) will increase proliferation concerns. After studying the feasibility of using thorium, nuclear scientists Ralph W. Moir and Edward Teller suggested that thorium nuclear research should be restarted after a three-decade shutdown and that a small prototype plant should be built.
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  • 18 Oct 2022
Topic Review
Angry Black Woman
The angry black woman stereotype is a trope in American society that portrays African-American women as sassy, ill-mannered, and ill-tempered by nature. Related concepts are the "sapphire" or "sassy black woman". Scholars Dionne Bennett and Marcyliena Morgan suggest that the stereotype is less studied than the mammy and Jezebel archetypes because researchers accept it as true. Carolyn West defines the Angry Black Woman as one variety of a Sapphire stereotype (another category listed is "Sistas with Attitude"). West defines the pervasive "Sapphire/ABW image" as "a template for portraying almost all Black women" and as serving several purposes. West sees it as "passion and righteous indignation... often misread as irrational anger... used to silence and shame Black women who dare to challenge social inequalities, complain about their circumstances, or demand fair treatment (Harris-Perry, 2011). Defined by Pilgrim (2015), "it is a social control mechanism that is employed to punish black women who violate the societal norms that encourage them to be passive, servile, nonthreatening, and unseen" (p. 121). It has been characterized as leading to a form of double bind.
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  • 11 Nov 2022
Topic Review
Black Tiger (Animal)
A black tiger is a rare colour variant of the tiger and is not a distinct species or geographic subspecies.
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  • 18 Oct 2022
Topic Review
Italic Languages
The Italic languages are a subfamily of the Indo-European language family, originally spoken by Italic peoples. They include Latin and its descendants (the Romance languages) as well as a number of extinct languages of the Italian Peninsula, including Umbrian, Oscan, Faliscan, South Picene, and possibly Venetic and Sicel. With over 800 million native speakers, the Italic languages are the second most widely spoken branch of the Indo-European family, after the Indo-Iranian languages. In the past, various definitions of "Italic" have prevailed. This article uses the classification presented by the Linguist List: Italic includes the Latin subgroup (Latin and the Romance languages) as well as the ancient Italic languages (Faliscan, Osco-Umbrian and two unclassified Italic languages, Aequian and Vestinian). Venetic (the language of the ancient Veneti), as revealed by its inscriptions, shared some similarities with the Italic languages and is sometimes classified as Italic. However, since it also shares similarities with other Western Indo-European branches (particularly Celtic languages), some linguists prefer to consider it as an independent Indo-European language. In the extreme view, Italic did not exist, but the different groups descended directly from Indo-European and converged because of geographic contiguity. That view stems in part from the difficulty in identifying a common Italic homeland in prehistory. In the intermediate view, the Italic languages are one of the ten or eleven major subgroups of the Indo-European language family and might therefore have had an ancestor, Common Italic or Proto-Italic from which its daughter languages descended. Moreover, there are similarities between major groups, but how the similarities are to be interpreted is one of the major debated issues in the historical linguistics of Indo-European. The linguist Calvert Watkins went so far as to suggest, among the ten major groups, a four-way division of East, West, North and South Indo-European. He considered them to be "dialectical divisions within Proto-Indo-European which go back to a period long before the speakers arrived in their historical areas of attestation". It is not to be considered a nodular grouping; in other words, there was not necessarily any common west Indo-European serving as a node from which the subgroups branched but a hypothesised similarity between the dialects of Proto-Indo-European that developed into the recognised families. Although generally regarded as a single branch that diversified from a Common or Proto-Italic stage, after the Proto-Indo-European period, some authors doubt this common affiliation. All the Italic languages share a number of common isoglosses; thus, all of them are centum languages that do not present palatalization of the Indo-European (palatal) velars /*k, *kʷ, *g, *gʰ, *gʰʷ/. The Romance languages present a later palatalization of Latin phonemes /k, g/, although only before phonemes /ɛ, e, i/.
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  • 17 Nov 2022
Topic Review
Deep Sea Fish
Deep-sea fish are animals that live in the darkness below the sunlit surface waters, that is below the epipelagic or photic zone of the sea. The lanternfish is, by far, the most common deep-sea fish. Other deep sea fishes include the flashlight fish, cookiecutter shark, bristlemouths, anglerfish, viperfish, and some species of eelpout. Only about 2% of known marine species inhabit the pelagic environment. This means that they live in the water column as opposed to the benthic organisms that live in or on the sea floor. Deep-sea organisms generally inhabit bathypelagic (1000–4000m deep) and abyssopelagic (4000–6000m deep) zones. However, characteristics of deep-sea organisms, such as bioluminescence can be seen in the mesopelagic (200–1000m deep) zone as well. The mesopelagic zone is the disphotic zone, meaning light there is minimal but still measurable. The oxygen minimum layer exists somewhere between a depth of 700m and 1000m deep depending on the place in the ocean. This area is also where nutrients are most abundant. The bathypelagic and abyssopelagic zones are aphotic, meaning that no light penetrates this area of the ocean. These zones make up about 75% of the inhabitable ocean space. The epipelagic zone (0–200m) is the area where light penetrates the water and photosynthesis occurs. This is also known as the photic zone. Because this typically extends only a few hundred meters below the water, the deep sea, about 90% of the ocean volume, is in darkness. The deep sea is also an extremely hostile environment, with temperatures that rarely exceed 3 °C (37.4 °F) and fall as low as −1.8 °C (28.76 °F) (with the exception of hydrothermal vent ecosystems that can exceed 350 °C, or 662 °F), low oxygen levels, and pressures between 20 and 1,000 atmospheres (between 2 and 100 megapascals).
  • 6.1K
  • 08 Nov 2022
Topic Review
Gas Turbines with Water Injection and Full Evaporation
The concept behind humidifying gas turbines is that increasing the amount of water/steam injected into the turbine increases the amount of mass it moves. This results in a rise in the specific power output because the effort exerted by the compressor remains the same, and it takes far less effort to raise the pressure of a liquid than it does of a gas. The efficiency of the cycle may be improved by recovering the energy contained in the gas turbine’s exhaust and either preheating the injection water, making injection steam, or the recuperator’s preheating of the combustion oxidizer. The introduction of water prior to the combustor of a recuperated gas turbine lowers the compressed air’s temperature at the input of the recuperator. This results in an increase in the rate at which energy is recovered from the exhaust gas.
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  • 27 Dec 2022
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