Presentation of a monoid
In the context of algebra, a **monoid** is a specific type of algebraic structure that consists of a set, an associative binary operation, and an identity element. The formal definition can be broken down into the following components: 1. **Set**: A non-empty set \( M \).
Quantum Markov semigroup
A **Quantum Markov semigroup** is a mathematical object used in the study of open quantum systems, where the dynamics of a quantum system are influenced by its interaction with an environment. These semigroups are a generalization of classical Markov processes adapted to the framework of quantum mechanics. ### Key Concepts 1. **Quantum Systems**: In the quantum context, a system is represented by a Hilbert space and is described by a density operator (mixed state) on that space.
Rees factor semigroup
The Rees factor semigroup is a mathematical structure studied in the field of algebra, specifically in semigroup theory. It is named after the mathematician R. J. Rees, who contributed to the development of semigroup theory. A Rees factor semigroup is constructed from a semigroup \( S \) and a congruence relation \( \theta \) on \( S \).
Community (ecology)
In ecology, a community refers to an assemblage of different species living together in a particular habitat or ecosystem. These species can include plants, animals, fungi, and microorganisms that interact with one another in various ways, including competition, predation, mutualism, and commensalism. Communities are characterized by their species diversity (the variety of species present), species composition (the identity and abundance of each species), and the interactions among the species.
Self-perpetuation
Self-perpetuation refers to a process or mechanism by which an entity, organization, system, or idea continues to exist or endure independently over time without external intervention. In various contexts, it can imply that the entity has the means to sustain itself, reproduce its characteristics, or propagate its influence and existence. For example: 1. **Biological Context**: In ecology, self-perpetuation can describe populations that maintain their numbers and genetic diversity through reproduction without the need for external input.
Social network aggregation
Social network aggregation refers to the process of combining data and content from multiple social media platforms into a single interface or service. This allows users to manage and interact with their various social media accounts in one place. Social network aggregators help streamline the user experience by enabling users to view updates, post content, and engage with friends or followers across different networks without needing to switch between multiple platforms.
Social network analysis
Social Network Analysis (SNA) is a methodological approach used to investigate and analyze social structures through the use of network and graph theories. It involves the mapping and measuring of relationships and flows between people, groups, organizations, or other entities. SNA focuses on the connections and patterns within these networks, rather than just the individual entities themselves.
The Spatial-Numerical Association of Response Codes (SNARC) refers to a psychological phenomenon observed in cognitive science that suggests people have an inherent tendency to associate numerical values with spatial locations. This effect is particularly noted in how individuals perceive and respond to numbers. The basic premise of SNARC is that smaller numbers are associated with the left side of space, while larger numbers are associated with the right side. This can be demonstrated through various experimental tasks, such as number comparison or reaction time tasks.
Spontaneous order
Spontaneous order refers to the self-organization that arises in complex systems without central planning or intervention. It is a concept often discussed in economics, philosophy, sociology, and systems theory. The idea is that when individuals act independently based on their own desires, preferences, and knowledge, complex patterns and structures can emerge naturally from their interactions. A commonly cited example of spontaneous order is the market economy. In a free market, individuals pursue their own interests while producing goods and services that others value.
Stigmergy
Stigmergy is a concept derived from social insect behavior, particularly in relation to how certain species, like ants or termites, coordinate their activities without direct communication. The term was first introduced by the French biologist Pierre-Paul Grassé in the 1950s. It describes a mechanism of indirect collaboration where the actions of individual agents (such as workers in a colony) leave environmental cues or modifications that influence the behavior of others.
Supramolecular assembly
Supramolecular assembly refers to the organized structure formed through non-covalent interactions between molecules, often termed supramolecules. Unlike traditional molecular assembly, which involves covalent bonds, supramolecular chemistry utilizes weaker interactions such as hydrogen bonding, van der Waals forces, π-π stacking, hydrophobic effects, and coordination bonds. This allows for the formation of complex architectures from simpler building blocks.
Frances Hugle
As of my last update in October 2021, there is no widely recognized information about an entity or notable person named "Frances Hugle." It’s possible that new developments or figures have emerged since then, or that "Frances Hugle" may refer to a private individual or a lesser-known entity. If you can provide more context or specify the area in which you are referring (e.g.
I. M. Dharmadasa
I. M. Dharmadasa is a name that may refer to an individual, but without additional context, it is unclear who specifically you are asking about. There could be various individuals with that name across different fields such as academia, literature, or other professions.
James F. Gibbons
James F. Gibbons could refer to various individuals, but one notable person is the American businessman and politician. His prominence typically comes from his involvement in political or business contexts. Without more specific information, it's challenging to pinpoint which James F. Gibbons you might be referring to, as individuals with that name could have varied backgrounds in different fields, such as academia, politics, or business.
Great American Interchange
The Great American Interchange, also known as the Great American Biotic Interchange, refers to a significant period during the late Cenozoic Era, approximately 3 million years ago, when animals and plants migrated between North America and South America. This exchange was facilitated by the formation of the Isthmus of Panama, which connected the two continents.
Donor (semiconductors)
In the context of semiconductors, a "donor" refers to an atom or impurity that is introduced into a semiconductor material (typically silicon or germanium) to create n-type (negative-type) semiconductor material. When donor atoms, which typically have five valence electrons (such as phosphorus, arsenic, or antimony), are added to the semiconductor lattice, they donate one extra electron that is not needed for bonding with the surrounding silicon atoms.
Dopant
A dopant is a material that is added in small quantities to a semiconductor to modify its electrical properties. This process is known as doping. The primary purpose of doping is to control the concentration of charge carriers in the semiconductor material, which can enhance its conductivity. In semiconductors, the two main types of dopants are: 1. **N-type dopants**: These have extra electrons, which can increase the number of free electrons in the semiconductor.
Dopant activation
Dopant activation refers to the process of making a dopant atom incorporated into a semiconductor material electrically active. Dopants are impurities added to a semiconductor (like silicon or gallium arsenide) to modify its electrical properties; they can donate free charge carriers (electrons or holes) that enhance the material's conductivity. When dopants are introduced into a semiconductor, they typically occupy specific lattice sites.
Extended Hückel method
The Extended Hückel method (EHM) is a semi-empirical quantum chemistry technique used to estimate the electronic structure of molecules, particularly organic compounds and some inorganic systems. It is an extension of the original Hückel molecular orbital (HMO) theory, which was primarily developed for planar conjugated systems. The Extended Hückel method broadens this approach to accommodate three-dimensional systems and allows for a more accurate representation of interactions between atomic orbitals.
MNDO
MNDO stands for Modified Neglect of Diatomic Overlap. It is a quantum chemistry method used for molecular modeling, particularly in the field of computational chemistry. MNDO is a type of semi-empirical method, which means it uses empirical data to simplify the quantum mechanical calculations of molecular systems. The MNDO method approximates the electronic structure of molecules by focusing on the interactions between atoms while neglecting the overlap of electron clouds between certain pairs of atoms.