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Topic Review
Relational Theory
In physics and philosophy, a relational theory (or relationism) is a framework to understand reality or a physical system in such a way that the positions and other properties of objects are only meaningful relative to other objects. In a relational spacetime theory, space does not exist unless there are objects in it; nor does time exist without events. The relational view proposes that space is contained in objects and that an object represents within itself relationships to other objects. Space can be defined through the relations among the objects that it contains considering their variations through time. The alternative spatial theory is an absolute theory in which the space exists independently of any objects that can be immersed in it. The relational point of view was advocated in physics by Gottfried Wilhelm Leibniz and Ernst Mach (in his Mach's principle). It was rejected by Isaac Newton in his successful description of classical physics. Although Albert Einstein was impressed by Mach's principle, he did not fully incorporate it into his general theory of relativity. Several attempts have been made to formulate a full Machian theory, but most physicists think that none have so far succeeded. For example, see Brans–Dicke theory. Relational quantum mechanics and a relational approach to quantum physics have been independently developed, in analogy with Einstein's special relativity of space and time. Relationist physicists such as John Baez and Carlo Rovelli have criticised the leading unified theory of gravity and quantum mechanics, string theory, as retaining absolute space. Some prefer a developing theory of gravity, loop quantum gravity for its 'backgroundlessness'. A recent synthesis of relational theory, called R-theory, continuing the work of the mathematical biologist Robert Rosen (who developed "relational biology" and "relational complexity" as theories of life) takes a position between the above views. Rosen's theory differed from other relational views in defining fundamental relations in nature (as opposed to merely epistemic relations we might discuss) as information transfers between natural systems and their organization (as expressed in models). R-theory extends the idea of organizational models to nature generally. As interpreted by R-theory, such "modeling relations" describe reality in terms of information relations (encoding and decoding) between measurable existence (expressed as material states and established by efficient behavior) and implicate organization or identity (expressed as formal potential and established by final exemplar), thus capturing all four of Aristotle's causalities within nature (Aristotle defined final cause as immanent from outside of nature). Applied to space-time physics, it claims that space-time is real but established only in relation to existing events, as a formal cause or model for the location of events relative to each other; and in reverse a system of space-time events establishes a template for space-time. R-theory is thus a form of model-dependent realism. It claims to more closely follow the views of Mach, Leibniz, Wheeler and Bohm, suggesting that natural law itself is system-dependent.
  • 4.2K
  • 21 Oct 2022
Topic Review
Walkable Cities
Reductions in walking trips have coincided with unprecedented levels of car trips, that caused several harmful environmental and health impacts. Walking is a simple, healthy and sustainable mode of transport that can be used for short urban trips or in combination with public transport for longer distances. The promotion of walkable cities encourages pedestrian activity, provides access to services and other businesses and satisfies daily needs without requiring to use a car.
  • 4.2K
  • 13 Sep 2022
Topic Review
Censorship of Twitter
Censorship of Twitter refers to Internet censorship by governments that block access to Twitter. Twitter censorship also includes governmental notice and take down requests to Twitter, which Twitter enforces in accordance with its Terms of Service when a government or authority submits a valid removal request to Twitter indicating that specific content (such as a tweet) is illegal in their jurisdiction.
  • 4.2K
  • 11 Nov 2022
Topic Review
Mie–Gruneisen Equation of State
The Mie–Grüneisen equation of state is a relation between the pressure and the volume of a solid at a given temperature. It is used to determine the pressure in a shock-compressed solid. The Mie–Grüneisen relation is a special form of the Grüneisen model which describes the effect that changing the volume of a crystal lattice has on its vibrational properties. Several variations of the Mie–Grüneisen equation of state are in use. The Grüneisen model can be expressed in the form where V is the volume, p is the pressure, e is the internal energy, and Γ is the Grüneisen parameter which represents the thermal pressure from a set of vibrating atoms. If we assume that Γ is independent of p and e, we can integrate Grüneisen's model to get where p0 and e0 are the pressure and internal energy at a reference state usually assumed to be the state at which the temperature is 0K. In that case p0 and e0 are independent of temperature and the values of these quantities can be estimated from the Hugoniot equations. The Mie–Grüneisen equation of state is a special form of the above equation.
  • 4.2K
  • 22 Nov 2022
Topic Review
Ultra-processed Foods
Ultra-processed foods were first defined by Dr. Carlos Monteiro in 2009 through the NOVA classification. Briefly, they are characterized in their formulation by the addition of cosmetic ingredients and/or additives for mainly industrial use - and having undergone an excessive processing  - to imitate, exacerbate, mask or restore sensory properties (aroma, texture, taste and color). It can also be very denaturing technological processes directly applied to the food (cooking-extrusion, puffing, etc.). They are food and drink products that have undergone specified types of food processing, usually by transnational and other very large 'Big food' corporations. These foods are designed to be 'convenient, eaten on the go, hyperpalatable and appealing to consumers, and, most importantly, the most profitable segment of Big Food companies’ portfolios because of these foods’ low-cost ingredients'. The NOVA-derived Siga score propose a complementary definition more focused ont the degradation of the food/ingredient matrix effect: "An ultra-processed food is characterized by the presence in its list of ingredients of at least one substance that is itself ultra-processed, called a marker of ultra-processing (MUP). These MUPs are obtained by synthesis, or by a succession of physical, chemical and/or biological processes applied to natural raw materials and which lead to a strong degradation compared to their original matrix".
  • 4.2K
  • 29 Oct 2020
Topic Review
Large-Scale Piezoelectric-Based Aircraft Systems
A new approach in the development of aircraft and aerospace industry is geared toward increas-ing use of electric systems. An electromechanical (EM) piezoelectric-based system is one of the po-tential technologies that can produce a compactable system with a fast response and a high power density. However, piezoelectric materials generate a small strain, of around 0.1–0.2% of the original actuator length, limiting their potential in large-scale applications.
  • 4.2K
  • 20 Feb 2021
Topic Review
Clear-channel station
A clear-channel station is an AM radio station in North America that has the highest protection from interference from other stations, particularly concerning night-time skywave propagation. The system exists to ensure the viability of cross-country or cross-continent radio service, and is enforced through a series of treaties and statutory laws. Now known as Class A stations since 1982, they are occasionally still referred to by their former classifications of Class I-A (the highest classification), Class I-B (the next highest class), or Class I-N (for stations in Alaska too far away to cause interference to the primary clear-channel stations in the lower 48 states). The term "clear-channel" is used most often in the context of North America and the Caribbean, where the concept originated. Since 1941, these stations have been required to maintain at least 10,000 watts of power to retain their status. Nearly all these stations in the United States , Canada and The Bahamas broadcast at 50,000 watts, with several clear-channel stations in Mexico going as high as 150,000 watts and XEW in Mexico City operating at 250,000 watts for over 80 years. (Cuba was originally included in the plan and had several stations given clear-channel status, but Cuba stopped participating after 1959.)
  • 4.2K
  • 08 Oct 2022
Topic Review
State of Nature
The state of nature, in moral and political philosophy, religion, social contract theories and international law, is the hypothetical life of people before societies came into existence. Philosophers of the state of nature theory deduce that there must have been a time before organized societies existed, and this presumption thus raises questions such as: "What was life like before civil society?"; "How did government first emerge from such a starting position?," and; "What are the hypothetical reasons for entering a state of society by establishing a nation-state?". In some versions of social contract theory, there are no rights in the state of nature, only freedoms, and it is the contract that creates rights and obligations. In other versions the opposite occurs: the contract imposes restrictions upon individuals that curtail their natural rights. Societies existing before or without a political state are currently studied in such fields as paleolithic history, and the anthropological subfields of archaeology, cultural anthropology, social anthropology, and ethnology, which investigate the social and power-related structures of indigenous and uncontacted peoples living in tribal communities.
  • 4.2K
  • 11 Nov 2022
Topic Review
Climate Change Adaptation in Greenland
Climate change adaptation is a pressing issue in Greenland. The term climate change describes long-term changes to the climate system. Since the 1950s a stark rise in global temperatures has been observed. As climate change, whether natural or anthropogenic, impacts the livelihoods of people across the globe, responses i.e. ways to prepare and adjust under changing vulnerabilities become important. Such responses are commonly discussed under the term adaptation, "the process of adjustment to actual or expected climate and its effects", as defined by the IPCC. Geographically Greenland is situated between the Arctic and the Atlantic Ocean, with one third of the island being north of the Arctic Circle. Since the middle of the 20th century, the Arctic has been warming at about twice the global rate. Rising temperatures put increasing pressure on certain plant and tree species and contribute to Greenland's melting ice sheet. This affects and changes the livelihood of the Greenlandic population, particularly the Inuit people, which make up to 80 percent of the total population. Besides the decline of fish stocks, the country's landscape is changing: the melting ice reveals minerals, oil and gas. This has attracted interest from local and foreign investors for potential resource extraction. As new industries are accompanied by new job opportunities and potential wealth, lifestyles are changing. Greenland is in transition, in terms of biophysical as well as cultural and social conditions.
  • 4.2K
  • 20 Nov 2022
Topic Review
Ascribed Status
Ascribed status refers to the social position or rank assigned to an individual at birth or through inherent characteristics beyond their control, such as gender, race, or family background. Unlike achieved status, which is earned through individual effort or accomplishments, ascribed status shapes one's identity and societal roles independent of personal merit or achievement. These predetermined attributes often influence an individual's opportunities, privileges, and interactions within society.
  • 4.2K
  • 02 Feb 2024
Topic Review
Development of Therapeutic Monoclonal Antibodies
We provide an overview of the challenges and advancements in the development of therapeutic monoclonal antibodies and antibody products.
  • 4.2K
  • 21 Sep 2021
Topic Review
YOLOv5-AC
Attention Mechanism-Based Lightweight YOLOv5 for Track Pedestrian Detection. In response to the dangerous behavior of pedestrians roaming freely on unsupervised train tracks, the real-time detection of pedestrians is urgently required to ensure the safety of trains and people. Aiming to improve the low accuracy of railway pedestrian detection, the high missed-detection rate of target pedestrians, and the poor retention of non-redundant boxes, YOLOv5 is adopted as the baseline to improve the effectiveness of pedestrian detection by model pruning, improving attention mechanism, etc.
  • 4.2K
  • 15 Sep 2022
Topic Review
Depersonalization Disorder
Depersonalization disorder (DPD), also known as depersonalization/derealization disorder (DPDR), is a mental disorder in which the person has persistent or recurrent feelings of depersonalization or derealization. Depersonalization is described as feeling disconnected or detached from one's self. Individuals experiencing depersonalization may report feeling as if they are an outside observer of their own thoughts or body, and often report feeling a loss of control over their thoughts or actions. In some cases, individuals may be unable to accept their reflection as their own, or they may have out-of-body experiences. Derealization is described as detachment from one's surroundings. Individuals experiencing derealization may report perceiving the world around them as foggy, dreamlike/surreal, or visually distorted. In addition to these depersonalization-derealization disorder symptoms, the inner turmoil created by the disorder can result in depression, self-harm, low self-esteem, phobias, panic attacks, and suicide. It can also cause a variety of physical symptoms, including chest pain, blurry vision, visual snow, nausea, and the sensation of pins and needles in one's arms or legs. Depersonalization-derealization disorder is thought to be caused largely by interpersonal trauma such as childhood abuse. Triggers may include significant stress, panic attacks, and drug use. Studies suggest a uniform syndrome for chronic depersonalization/derealization regardless of whether drugs or an anxiety disorder is the precipitant. It is unclear whether genetics plays a role; however, there are many neurochemical and hormonal changes in individuals with depersonalization disorder. The disorder is typically associated with cognitive disruptions in early perceptual and attentional processes. Diagnostic criteria for depersonalization-derealization disorder include persistent or recurrent feelings of detachment from one's mental or bodily processes or from one's surroundings. A diagnosis is made when the dissociation is persistent and interferes with the social or occupational functions of daily life. However, accurate descriptions of the symptoms are hard to provide due to the subjective nature of depersonalization and derealization and persons' ambiguous use of language when describing these episodes. In the DSM-5, it was combined with derealization disorder and renamed "depersonalization/derealization disorder" ("DDPD"). In the DSM-5, it remains classified as a dissociative disorder, while the ICD-10 calls it "depersonalization-derealization syndrome" and classifies it as a neurotic disorder. Although the disorder is an alteration in the subjective experience of reality, it is not a form of psychosis, as the person is able to distinguish between their own internal experiences and the objective reality of the outside world. During episodic and continuous depersonalization, the person can distinguish between reality and fantasy and the grasp on reality remains stable at all times. While depersonalization-derealization disorder was once considered rare, lifetime experiences with it occur in about 1–2% of the general population. The chronic form of the disorder has a reported prevalence of 0.8 to 1.9%. While brief episodes of depersonalization or derealization can be common in the general population, the disorder is only diagnosed when these symptoms cause substantial distress or impair social, occupational, or other important areas of functioning.
  • 4.2K
  • 23 Nov 2022
Topic Review
Hybrid Ship Propulsion Systems
Following the trends in the automobile industry, hybrid electric propulsion systems have been proposed and used in ships to achieve higher efficiency, mitigate carbon emissions and reduce overall operational costs by combining traditional mechanical propulsion with electrical propulsion. Studies have been conducted on the diverse types of hybrid marine power systems to understand the behaviour of the ships at different operating and loading conditions to optimise the cost function of the hybrid system model. 
  • 4.2K
  • 06 Jan 2023
Topic Review
Biological Melatonin versus Synthetic Melatonin
Melatonin dietary supplements are widely consumed worldwide, with developed countries as the largest consumers, with an estimated annual growth rate of approximately 10% until 2027, mainly in developing countries. The wide use of melatonin against sleep disorders and particular problems, such as jet lag, has been added to other applications, such as anti-aging, anti-stress, immune system activation, anticancer, and others, which have triggered its use, normally without a prescription. The chemical industry currently covers 100% of the needs of the melatonin market.
  • 4.2K
  • 18 Apr 2023
Topic Review
Applications of Substrate-Integrated Waveguide
Substrate-integrated waveguide (SIW) is a modern day (21st century) transmission line that has recently been developed. This technology has introduced new possibilities to the design of efficient circuits and components operating in the radio frequency (RF) and microwave frequency spectrum. Microstrip components are very good for low frequency applications but are ineffective at extreme frequencies, and involve rigorous fabrication concessions in the implementation of RF, microwave, and millimeter-wave components. This is due to wavelengths being short at higher frequencies. Waveguide devices, on the other hand, are ideal for higher frequency systems, but are very costly, hard to fabricate, and challenging to integrate with planar components in the neighborhood. SIW connects the gap that existed between conventional air-filled rectangular waveguide and planar transmission line technologies including the microstrip.
  • 4.2K
  • 13 Apr 2022
Topic Review
Burn Pathophysiology
Burns are a widespread global public health traumatic injury affecting many people worldwide. Non-fatal burn injuries are a leading cause of morbidity, resulting in prolonged hospitalization, disfigurement, and disability, often with resulting stigma and rejection. The treatment of burns is aimed at controlling pain, removing dead tissue, preventing infection, reducing scarring risk, and tissue regeneration. 
  • 4.2K
  • 26 May 2023
Biography
Karl Sven Woytek Sas Konkovitch Matthew Kruszelnicki
Karl Sven Woytek Sas Konkovitch Matthew Kruszelnicki AM (born 1948), often referred to as "Dr Karl",[1] is an Australian science communicator and popularizer,[1] who is known as an author, and as a science commentator on Australian radio and television. Kruszelnicki is the Julius Sumner Miller Fellow in the Science Foundation for Physics at the School of Physics, University of Sydney.[2] Kru
  • 4.2K
  • 06 Dec 2022
Topic Review
Zinc Complexes as Anticancer Agents
The search for anticancer metal-based drugs alternative to platinum derivatives could not exclude zinc derivatives due to the importance of this metal for the correct functioning of the human body. Zinc, the second most abundant trace element in the human body, is one of the most important micro-elements essential for human physiology. Its ubiquity in thousands of proteins and enzymes is related to its chemical features, in particular, its lack of redox activity and its ability to support different coordination geometries and to promote fast ligands exchange. Analogously to other trace elements, the impairment of its homeostasis can lead to various diseases and in some cases can be also related to cancer development. However, zinc complexes generally exert lower toxicity in comparison to other metal-based drugs and many zinc derivatives have been proposed as antitumor agents. Among them zinc complexes  comprising  N-donor ligands have been surveyed and analyzed. 
  • 4.2K
  • 22 Dec 2020
Topic Review
Fallout Shelter (Video Game)
Fallout Shelter is a free-to-play simulation video game developed by Bethesda Game Studios, with assistance by Behaviour Interactive, and published by Bethesda Softworks. Part of the Fallout series, it was released worldwide for iOS devices in June 2015, for Android devices in August 2015, for Microsoft Windows in July 2016, Xbox One in February 2017, and PlayStation 4 and Nintendo Switch in June 2018. The game is also available on Tesla vehicles. The game tasks the player with building and effectively managing their own Vault, a fallout shelter. Upon release, Fallout Shelter received mostly positive reviews. Critics enjoyed the game's extension of the Fallout universe, the core gameplay, and its visual style. Common criticisms included the game's lack of depth, its use of unnecessary microtransactions, and its lack of an ending. The game grossed US$5.1 million (equivalent to about $5.5M in 2019) in microtransaction sales in the first two weeks after its release. While Fallout Shelter is a single-player experience, a multiplayer board game adaptation of the game was released about five years after its original release.
  • 4.2K
  • 30 Sep 2022
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