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Technicolor
Technicolor theories are models of physics beyond the Standard Model that address electroweak gauge symmetry breaking, the mechanism through which W and Z bosons acquire masses. Early technicolor theories were modelled on quantum chromodynamics (QCD), the "color" theory of the strong nuclear force, which inspired their name. Instead of introducing elementary Higgs bosons to explain observed phenomena, technicolor models were introduced to dynamically generate masses for the W and Z bosons through new gauge interactions. Although asymptotically free at very high energies, these interactions must become strong and confining (and hence unobservable) at lower energies that have been experimentally probed. This dynamical approach is natural and avoids issues of Quantum triviality and the hierarchy problem of the Standard Model. However, since the Higgs boson discovery at the CERN LHC in 2012, the original models are largely ruled out. Nonetheless, it remains a possibility that the Higgs boson is a composite state. In order to produce quark and lepton masses, technicolor or composite Higgs models have to be "extended" by additional gauge interactions. Particularly when modelled on QCD, extended technicolor was challenged by experimental constraints on flavor-changing neutral current and precision electroweak measurements. The specific extensions of particle dynamics for technicolor or composite Higgs bosons are unknown. Much technicolor research focuses on exploring strongly interacting gauge theories other than QCD, in order to evade some of these challenges. A particularly active framework is "walking" technicolor, which exhibits nearly conformal behavior caused by an infrared fixed point with strength just above that necessary for spontaneous chiral symmetry breaking. Whether walking can occur and lead to agreement with precision electroweak measurements is being studied through non-perturbative lattice simulations. Experiments at the Large Hadron Collider have discovered the mechanism responsible for electroweak symmetry breaking, i.e., the Higgs boson, with mass approximately 125 GeV/c2; such a particle is not generically predicted by technicolor models. However, the Higgs boson may be a composite state, e.g., built of top and anti-top quarks as in the Bardeen–Hill–Lindner theory. Composite Higgs models are generally solved by the top quark infrared fixed point, and may require a new dynamics at extremely high energies such as topcolor.
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  • 28 Sep 2022
Topic Review
NEC Engineering and Construction Contract
The New Engineering Contract (NEC), or NEC Engineering and Construction Contract, is a formalised system created by the UK Institution of Civil Engineers that guides the drafting of documents on civil engineering and construction projects for the purpose of obtaining tenders, awarding and administering contracts. As such they legally define the responsibilities and duties of Employers (who commission work) and Contractors (who carry out work) in the Works Information. The contract consists of two key parts the Contract Data part one (Data provided by the Employer) and Contract Data part two (Data provided by the Contractor). Several approaches are included making it a family of options. It is used in the UK and internationally in countries including New Zealand, Australia , Hong Kong and South Africa . There have been four editions, the first in 1993, the second in 1995, the third in 2005 and the most recent in 2017. The NEC3 was launched in 2005 and it was amended in April 2013. NEC4 was announced in March 2017 and has been available since June 2017. This new edition reflects procurement and project management developments and emerging best practice, with improvements in flexibility, clarity and the ease of administration. It also introduces two new contracts: NEC4 Design, Build and Operate (DBO) and NEC4 Alliance Contract (ALC).
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  • 28 Sep 2022
Topic Review
Action for Climate Empowerment
Action for Climate Empowerment (ACE) is a term adopted by the United Nations Framework Convention on Climate Change (UNFCCC). It refers to Article 6 of the Convention's original text (1992), focusing on six priority areas: education, training, public awareness, public participation, public access to information, and international cooperation on these issues. The implementation of all six areas has been identified as the pivotal factor for everyone to understand and participate in solving the complex challenges presented by climate change. The importance of ACE is reflected in other international frameworks such as the Sustainable Development Goals (SDGs, 2015); the Global Action Programme for Education for Sustainable Development (GAP on ESD, 2014); the Aarhus Convention (2011); the Escazú Agreement (2018) and the Bali Guidelines (2010). ACE calls on governments to develop and implement educational and public awareness programmes, train scientific, technical and managerial personnel, foster access to information, and promote public participation in addressing climate change and its effects. It also urges countries to cooperate in this process, by exchanging good practices and lessons learned, and strengthening national institutions. This wide scope of activities is guided by specific objectives that, together, are seen as crucial for effectively implementing climate adaptation and mitigation actions, and for achieving the ultimate objective of the UNFCCC.
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  • 28 Sep 2022
Topic Review
Holeum
Holeums are hypothetical stable, quantized gravitational bound states of primordial or micro black holes. Holeums were proposed by L. K. Chavda and Abhijit Chavda in 2002. They have all the properties associated with cold dark matter. Holeums are not black holes, even though they are made up of black holes.
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  • 28 Sep 2022
Topic Review
Vascular Plant
Vascular plants (from la vasculum 'duct'), also called tracheophytes (/trəˈkiː.əˌfaɪts/) or collectively Tracheophyta (from grc τραχεῖα ἀρτηρία) 'windpipe', and φυτά , form a large group of land plants (c. 300,000 accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified tissue (the phloem) to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms (including conifers) and angiosperms (flowering plants). Scientific names for the group include Tracheophyta,:251 Tracheobionta and Equisetopsida sensu lato. Some early land plants (the rhyniophytes) had less developed vascular tissue; the term eutracheophyte has been used for all other vascular plants, including all living ones. Historically, vascular plants were known as "higher plants," as it was believed that they were further evolved than other plants due to being more complex organisms. However, this is an antiquated remnant of the obsolete scala naturae, and the term is generally considered to be unscientific.
  • 1.8K
  • 29 Sep 2022
Topic Review
Shinsen
Shinsen (神饌 shinsen) are offerings given up to Shinto shrines or kamidana in Japan . They are also called mike or minie. The annual festivals carried out at different times of the year originated from Shinto rituals and festivals. As part of the ritual, locals would offer up food that had received a special blessing to welcome the kami ("gods" or "spirits"). Food offered up could range from their staple of rice to seafood, food foraged from the mountains, seasonal foods, local specialties, or food connected to the enshrined kami. At the end of the ritual, the offered food is eaten together to gain a sense of unity with the kami, and to gain their blessing and protection. The rite is known as naorai.
  • 1.3K
  • 28 Sep 2022
Topic Review
Emotion and Memory
Emotion can have a powerful effect on humans and animals. Numerous studies have shown that the most vivid autobiographical memories tend to be of emotional events, which are likely to be recalled more often and with more clarity and detail than neutral events. The activity of emotionally enhanced memory retention can be linked to human evolution; during early development, responsive behavior to environmental events would have progressed as a process of trial and error. Survival depended on behavioral patterns that were repeated or reinforced through life and death situations. Through evolution, this process of learning became genetically embedded in humans and all animal species in what is known as flight or fight instinct. Artificially inducing this instinct through traumatic physical or emotional stimuli essentially creates the same physiological condition that heightens memory retention by exciting neuro-chemical activity affecting areas of the brain responsible for encoding and recalling memory. This memory-enhancing effect of emotion has been demonstrated in many laboratory studies, using stimuli ranging from words to pictures to narrated slide shows, as well as autobiographical memory studies. However, as described below, emotion does not always enhance memory.
  • 2.2K
  • 28 Sep 2022
Topic Review
Fine-tuned Universe
The fine-tuned universe is the proposition that the conditions that allow life in the universe can occur only when certain universal dimensionless physical constants lie within a very narrow range of values, so that if any of several fundamental constants were only slightly different, the universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is understood. Various possible explanations of ostensible fine-tuning are discussed among philosophers, scientists, theologians, and proponents and detractors of creationism. The fine-tuned universe observation is closely related to, but is not exactly synonymous with, the anthropic principle, which is often used as an explanation of apparent fine-tuning.
  • 16.0K
  • 28 Sep 2022
Topic Review
Mithyatva
Mithyatva means "false belief", and an important concept in Jainism and Hinduism. Disappearance (nivrtti) is the necessary presupposition of mithyatva because what is falsely perceived ceases to exist with the dawn of right knowledge. Mithyatva, states Jayatirtha, cannot be easily defined as 'indefinable', 'non-existent', 'something other than real', 'which cannot be proved, produced by avidya or as its effect', or as 'the nature of being perceived in the same locus along with its own absolute non-existence'. Mithyatva is a concept in Jainism distinguishing right knowledge from false knowledge, and parallels the concepts of Avidya in the Vedanta school of Hinduism, Aviveka in its Samkhya school, and Maya in Buddhism. The opposite of Mithyatva (false belief) is Samyaktva (right belief).
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  • 28 Sep 2022
Topic Review
Nuclear Football
The nuclear football (also known as the atomic football, the President's emergency satchel, the Presidential Emergency Satchel, the button, the black box, or just the football) is a briefcase, the contents of which are to be used by the President of the United States to authorize a nuclear attack while away from fixed command centers, such as the White House Situation Room. It functions as a mobile hub in the strategic defense system of the United States . It is held by an aide-de-camp.
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  • 28 Sep 2022
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