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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State-Dependent Memory
State-dependent memory or state-dependent learning is the phenomenon through which memory retrieval is most efficient when an individual is in the same state of consciousness as they were when the memory was formed. The term is often used to describe memory retrieval while in states of consciousness produced by psychoactive drugs – most commonly, alcohol, but has implications for mood or non-substance induced states of consciousness as well. Unlike context-dependent memory, which involves an individual's external environment and conditions, state-dependent memory applies to the individual's internal conditions. For example, while context-dependent memory might refer to the idea that taking a test in the same room that an individual studied in will make it easier to retrieve those memories, state-dependent learning refers to the idea that if an individual always studied for a test while slightly caffeinated, it will most likely be easiest to recall what they studied during the test if they are at a similar level of caffeination.
  • 14.0K
  • 24 Oct 2022
Topic Review
Puppet
In computing, Puppet is a software configuration management tool which includes its own declarative language to describe system configuration. It is a model-driven solution that requires limited programming knowledge to use. Puppet is produced by Puppet, Inc, founded by Luke Kanies in 2005. Its primary product, Puppet Enterprise, is a proprietary and closed-source version of its open-source Puppet software. They use Puppet's declarative language to manage stages of the IT infrastructure lifecycle, including the provisioning, patching, configuration, and management of operating system and application components in data centers and cloud infrastructures. Puppet uses an open-core model; its free-software version was released under version 2 of the GNU General Public License (GPL) until version 2.7.0, and later releases use the Apache License, while Puppet Enterprise uses a proprietary license. Puppet and Puppet Enterprise operate on multiple Unix-like systems (including Linux, Solaris, BSD, Mac OS X, AIX, HP-UX) and has Microsoft Windows support. Puppet itself is written in Ruby, while Facter is written in C++, and Puppet Server and Puppet DB are written in Clojure.
  • 1.6K
  • 20 Oct 2022
Topic Review
Comparison of Remote Sensing Satellites
A variety of remote sensing systems exist, for which the specification is distributed among a variety of websites from data providers, satellite operators and manufacturers. In order to choose a data product for a given project, a remote sensing data user must be aware of the different products and their applications. The table below gives users an overview of major remote sensing systems and datasets and summarizes their applications and systems.
  • 2.2K
  • 20 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.
  • 6.0K
  • 20 Oct 2022
Topic Review
BFR Satellite Delivery Spacecraft
The Big Falcon Rocket (officially shortened to BFR) is a privately funded fully reusable launch vehicle and spacecraft system in development by SpaceX. The overall space vehicle architecture includes both launch vehicles and spacecraft, as well as ground infrastructure for rapid launch and relaunch, and zero-gravity propellant transfer technology to be deployed in low Earth orbit (LEO). The payload capacity to Earth orbit of at least 100,000 kg (220,000 lb) makes BFR a super heavy-lift launch vehicle. The first orbital flight is tentatively planned for 2020. SpaceX has been developing a super heavy-lift launch vehicle for many years, with the exact design and nomenclature of the vehicle undergoing multiple revisions over time. Before 2016, the vehicle was referred to as the Mars Colonial Transporter (MCT), though very few details about the design of the MCT were ever made public. Starting from 2016, SpaceX began sharing annual updates with the public, detailing the designs and uses of their upcoming new launch vehicle. In 2016, SpaceX CEO Elon Musk presented the vehicle at the International Astronautical Congress as the ITS launch vehicle, forming a core part of Musk's comprehensive vision for an Interplanetary Transport System (ITS). The ITS vehicle had a 12-meter (39 ft) core diameter, but was only intended for interplanetary travel. In September 2017, the design (now known as the BFR) was scaled down to 9 meters (30 ft) While the ITS had been solely aimed at Mars transit and other interplanetary uses, SpaceX pivoted to a plan that would support all SpaceX launch service provider capabilities with a single set of 9-meter vehicles: Earth orbit, lunar orbit, Interplanetary spaceflight, and potentially, even intercontinental passenger transport on Earth. In September 2018, a redesign of the second stage was announced, adding steerable canards, two radially adjustable fins also acting as landing legs, and a third leg that looks like a vertical stabilizer but has no aerodynamic function due to the special re-entry profile of the spacecraft. The launch vehicle design is dependent on the concurrent development work on the Raptor rocket engines, which are cryogenic methalox-fueled engines to be used for both stages of the BFR launch vehicle. Development on the Raptor began in 2012, leading to engine testing which began in 2016. The BFR system is intended to completely replace all of SpaceX's existing space hardware (the Falcon 9 and Falcon Heavy launch vehicles, and the Dragon spacecraft), initially aiming at the Earth-orbit launch market, but explicitly adding substantial capability to support long-duration spaceflight in the cislunar and Mars transport flight environments.
  • 744
  • 20 Oct 2022
Topic Review
Maquis Du Vercors
The Maquis du Vercors was a rural group of the French Forces of the Interior (FFI) (maquis) that resisted the 1940–1944 German occupation of France in World War II. The Maquis du Vercors used the prominent scenic plateau known as the Massif du Vercors (Vercors Plateau) as a refuge. Initially the maquis carried out only sabotage and partisan operations against the Germans, but after the Normandy Invasion on 6 June 1944, the leadership of an army of about 4,000 maquis declared the "Free Republic of Vercors," raised the French flag, and attempted to create a conventional army to oppose the German occupation. The allies supported the maquis with parachute drops of weapons and by supplying teams of advisors and trainers, but the uprising was premature. In July 1944 as many as 10,000 German soldiers invaded the massif and killed more than 600 of the maquis, known as maquisards, and 200 civilians. It was German's largest anti-partisan operation in Western Europe during World War II. In August 1944, shortly after the battle for the Vercors, the area was liberated from German control by the American army allied with the FFI.
  • 4.1K
  • 20 Oct 2022
Topic Review
Notation for Theoretic Scheduling Problems
A convenient notation for theoretic scheduling problems was introduced by Ronald Graham, Eugene Lawler, Jan Karel Lenstra and Alexander Rinnooy Kan in. It consists of three fields: α, β and γ. Each field may be a comma separated list of words. The α field describes the machine environment, β the job characteristics and constraints, and γ the objective function. Since its introduction in the late 1970s the notation has been constantly extended, sometimes inconsistently. As a result, today there are some problems that appear with distinct notations in several papers.
  • 2.4K
  • 20 Oct 2022
Topic Review
Empirical Theory of Perception
An empirical theory of perception is a type of explanation for how percepts form. These theories hold that sensory systems incorporate information about the statistical properties of the natural world into their design and relate incoming stimuli to this information, rather than analyzing sensory stimulation into its components or features.
  • 2.3K
  • 20 Oct 2022
Topic Review
Gender-bias in Medical Diagnosis
Gender-biased diagnosing is a controversial sociological observation which asserts that medical and psychological diagnosis may be influenced by the gender of the patient. Several studies have found evidence of differential diagnosis for patients with similar ailments but of different sexes.
  • 2.8K
  • 20 Oct 2022
Topic Review
Glossitis Areata Exfoliativa
Geographic tongue, also known by several other terms, is a condition of the mucous membrane of the tongue, usually on the dorsal surface. It is a common condition, affecting approximately 2–3% of the general population. It is characterized by areas of smooth, red depapillation (loss of lingual papillae) which migrate over time. The name comes from the map-like appearance of the tongue, with the patches resembling the islands of an archipelago. The cause is unknown, but the condition is entirely benign (importantly, it does not represent oral cancer), and there is no curative treatment. Uncommonly, geographic tongue may cause a burning sensation on the tongue, for which various treatments have been described with little formal evidence of efficacy.
  • 3.1K
  • 24 Oct 2022
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