Summary

HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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SoundCloud
SoundCloud is an online audio distribution platform and music sharing website based in Berlin, Germany that enables its users to upload, promote, and share audio.
  • 8.5K
  • 20 Oct 2022
Topic Review
History of Zoology (Through 1859)
The history of zoology before Charles Darwin's 1859 theory of evolution traces the organized study of the animal kingdom from ancient to modern times. Although the concept of zoology as a single coherent field arose much later, systematic study of zoology is seen in the works of Aristotle and Galen in the ancient Greco-Roman world. This work was developed in the Middle Ages by Islamic medicine and scholarship, and in turn their work was extended by European scholars such as Albertus Magnus. During the European Renaissance and early modern period, zoological thought was revolutionized in Europe by a renewed interest in empiricism and the discovery of many novel organisms. Prominent in this movement were the anatomist Vesalius and the physiologist William Harvey, who used experimentation and careful observation, and naturalists such as Carl Linnaeus and Buffon who began to classify the diversity of life and the fossil record, as well as the development and behavior of organisms. Microscopy revealed the previously unknown world of microorganisms, laying the groundwork for cell theory. The growing importance of natural theology, partly a response to the rise of mechanical philosophy, encouraged the growth of natural history (although it entrenched the argument from design). Over the 18th and 19th centuries, zoology became increasingly professional scientific disciplines. Explorer-naturalists such as Alexander von Humboldt investigated the interaction between organisms and their environment, and the ways this relationship depends on geography—laying the foundations for biogeography, ecology and ethology. Naturalists began to reject essentialism and consider the importance of extinction and the mutability of species. Cell theory provided a new perspective on the fundamental basis of life. These developments, as well as the results from embryology and paleontology, were synthesized in Charles Darwin's theory of evolution by natural selection. In 1859, Darwin placed the theory of organic evolution on a new footing, by his discovery of a process by which organic evolution can occur, and provided observational evidence that it had done so.
  • 8.9K
  • 21 Apr 2023
Topic Review
Timoshenko-Ehrenfest Beam Theory
The Timoshenko-Ehrenfest beam theory was developed by Stephen Timoshenko and Paul Ehrenfest early in the 20th century. The model takes into account shear deformation and rotational bending effects, making it suitable for describing the behaviour of thick beams, sandwich composite beams, or beams subject to high-frequency excitation when the wavelength approaches the thickness of the beam. The resulting equation is of 4th order but, unlike Euler–Bernoulli beam theory, there is also a second-order partial derivative present. Physically, taking into account the added mechanisms of deformation effectively lowers the stiffness of the beam, while the result is a larger deflection under a static load and lower predicted eigenfrequencies for a given set of boundary conditions. The latter effect is more noticeable for higher frequencies as the wavelength becomes shorter (in principle comparable to the height of the beam or shorter), and thus the distance between opposing shear forces decreases. Rotary inertia effect was introduced by Bresse and Rayleigh. If the shear modulus of the beam material approaches infinity—and thus the beam becomes rigid in shear—and if rotational inertia effects are neglected, Timoshenko beam theory converges towards ordinary beam theory.
  • 28.3K
  • 20 Oct 2022
Topic Review
Metamerism
In biology, metamerism is the phenomenon of having a linear series of body segments fundamentally similar in structure, though not all such structures are entirely alike in any single life form because some of them perform special functions. In animals, metameric segments are referred to as somites or metameres. In plants, they are referred to as metamers or, more concretely, phytomers.
  • 1.4K
  • 20 Oct 2022
Topic Review
Sulcia Muelleri
"Candidatus Sulcia muelleri" is an aerobic, gram-negative, bacillus bacteria that is a part of the phylum Bacteroidetes. S. muelleri is an obligate and mutualistic symbiotic microbe commonly found occupying specialized cell compartments of sap-feeding insects called bacteriocytes. A majority of the research done on S. muelleri has detailed its relationship with the host Homalodisca vitripennis. Other studies have documented the nature of its residency in other insects like the maize leafhopper (Cicadulina) or the spittlebug (Cercopoidea). Sulcia muelleri is noted for its exceptionally minimal genome and it is currently identified as having the smallest known sequenced Bacteroidetes genome at only 245 kilobases.
  • 882
  • 20 Oct 2022
Topic Review
Johnson & Johnson COVID-19 vaccine
The Janssen or Johnson & Johnson COVID-19 vaccine is a COVID-19 vaccine that was developed by Janssen Vaccines in Leiden, Netherlands, and its Belgian parent company Janssen Pharmaceuticals, subsidiary of American company Johnson & Johnson. It is a viral vector vaccine based on a human adenovirus that has been modified to contain the gene for making the spike protein of the SARS-CoV-2 virus that causes COVID-19. The body's immune system responds to this spike protein to produce antibodies. The vaccine requires only one dose and does not need to be stored frozen. Clinical trials for the vaccine were started in June 2020, with Phase III trials involving around 43,000 people. On 29 January 2021, Janssen announced that 28 days after a completed vaccination, the vaccine was 66% effective in a one-dose regimen in preventing symptomatic COVID-19, with an 85% efficacy in preventing severe COVID-19, and 100% efficacy in preventing hospitalization or death caused by the disease. The vaccine has been granted an Emergency Use Authorization by the US Food and Drug Administration and a conditional marketing authorisation by the European Medicines Agency (EMA).
  • 639
  • 20 Oct 2022
Topic Review
Non-Linear Editing System
Non-linear editing is a form of offline editing for audio, video, and image editing. In offline editing, the original content is not modified in the course of editing. In non-linear editing, edits are specified and modified by specialized software. A pointer-based playlist, effectively an edit decision list (EDL), for video or a directed acyclic graph for still images is used to keep track of edits. Each time the edited audio, video, or image is rendered, played back, or accessed, it is reconstructed from the original source and the specified editing steps. Although this process is more computationally intensive than directly modifying the original content, changing the edits themselves can be almost instantaneous, and it prevents further generation loss as the audio, video, or image is edited. A non-linear editing system (NLE) is a video (NLVE) or audio editing (NLAE) digital audio workstation (DAW) system that performs non-destructive editing on source material. The name is in contrast to 20th century methods of linear video editing and film editing.
  • 1.7K
  • 25 Oct 2022
Topic Review
Lingua Franca
A lingua franca is any language widely used beyond the population of its native speakers. The de facto status of lingua franca is usually "awarded" by the masses to the language of the most influential nation(s) of the time. Any given language normally becomes a lingua franca primarily by being used for international commerce, but can be accepted in other cultural exchanges, especially diplomacy. Occasionally the term "lingua franca" is applied to a fully established formal language; thus formerly it was said that French was the lingua franca of diplomacy. The term "lingua franca" was originally used by Arabs to name all Romance languages, and especially Italian (Arabs used the name 'Franks' for all peoples in Western Europe). Then, it meant a language with a Romance lexicon (most words derived from Latin which then evolved into early forms of Spanish and Italian) and a very simple grammar, that till the end of the 19th century was used by mariners in the Mediterranean Sea, particularly in the Middle East and Northern Africa. A related concept is that of a “vehicular language.” It is defined as a basic linguistic structure for proposed “international auxiliary languages,” for example, the use of an Indo-European language, or Indo-European itself, in the development of Esperanto.
  • 9.0K
  • 20 Oct 2022
Topic Review
Force4
Force4 is a development system and framework for the rapid development of rich Internet applications for the connection of databases to different presentation technologies. It integrates the creation and reverse engineering of database models, the creation of the necessary objects and access classes and the composing of Rich Internet Applications.
  • 1.0K
  • 20 Oct 2022
Topic Review
Marine Algae and Plants
Marine algae and plants are a diverse collection of marine life that, together with cyanobacteria, form the main primary producers at base of the ocean food chain. Marine primary producers are important because they underpin almost all marine animal life by generating most of the oxygen and food that animals need to exist. Some algae and plants are also ecosystem engineers which change the environment and provide habitats for other marine life. Marine algae includes the largely invisible and often unicellular microalgae, which together with cyanobacteria form the ocean phytoplankton, as well as the larger, more visible and complex multicellular macroalgae commonly called seaweed. Seaweeds are found along coastal areas, living on the floor of continental shelves and washed up in intertidal zones. Some seaweeds drift with plankton in the sunlit surface waters (epipelagic zone) of the open ocean. Back in the Silurian, some phytoplankton evolved into red, brown and green algae. These algae then invaded the land and started evolving into the land plants we know today. Later in the Cretaceous some of these land plants returned to the sea as mangroves and seagrasses. These are found along coasts in intertidal regions and in the brackish water of estuaries. In addition, some seagrasses, like seaweeds, can be found at depths up to 50 metres on both soft and hard bottoms of the continental shelf.
  • 6.4K
  • 20 Oct 2022
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