title: Peer-to-peer

text: Tim Berners-Lee's vision for the World Wide Web was close to a P2P network in that it assumed each user of the web would be an active editor and contributor, creating and linking content to form an interlinked "web" of links. The early Internet was more open than the present day, where two machines connected to the Internet could send packets to each other without firewalls and other security measures. This contrasts to the broadcasting-like structure of the web as it has developed over the years. As a precursor to the Internet, ARPANET was a successful client-server network where "every participating node could request and serve content." However, ARPANET was not self-organized, and it lacked the ability to "provide any means for context or content-based routing beyond 'simple' address-based routing."


title: Peer-to-peer

text: Therefore, Usenet, a distributed messaging system that is often described as an early peer-to-peer architecture, was established. It was developed in 1979 as a system that enforces a decentralized model of control. The basic model is a client–server model from the user or client perspective that offers a self-organizing approach to newsgroup servers. However, news servers communicate with one another as peers to propagate Usenet news articles over the entire group of network servers. The same consideration applies to SMTP email in the sense that the core email-relaying network of mail transfer agents has a peer-to-peer character, while the periphery of Email clients and their direct connections is strictly a client-server relationship.


title: Peer-to-peer

text: In May 1999, with millions more people on the Internet, Shawn Fanning introduced the music and file-sharing application called Napster. Napster was the beginning of peer-to-peer networks, as we know them today, where "participating users establish a virtual network, entirely independent from the physical network, without having to obey any administrative authorities or restrictions."


title: Peer-to-peer

text: A peer-to-peer network is designed around the notion of equal "peer" nodes simultaneously functioning as both "clients" and "servers" to the other nodes on the network. This model of network arrangement differs from the client–server model where communication is usually to and from a central server. A typical example of a file transfer that uses the client-server model is the File Transfer Protocol (FTP) service in which the client and server programs are distinct: the clients initiate the transfer, and the servers satisfy these requests.


title: Peer-to-peer

text: Peer-to-peer networks generally implement some form of virtual overlay network on top of the physical network topology, where the nodes in the overlay form a subset of the nodes in the physical network. Data is still exchanged directly over the underlying TCP/IP network, but at the application layer peers are able to communicate with each other directly, via the logical overlay links (each of which corresponds to a path through the underlying physical network). Overlays are used for indexing and peer discovery, and make the P2P system independent from the physical network topology. Based on how the nodes are linked to each other within the overlay network, and how resources are indexed and located, we can classify networks as "unstructured" or "structured" (or as a hybrid between the two).


title: Peer-to-peer

text: "Unstructured peer-to-peer networks" do not impose a particular structure on the overlay network by design, but rather are formed by nodes that randomly form connections to each other. (Gnutella, Gossip, and Kazaa are examples of unstructured P2P protocols).


title: Peer-to-peer

text: Because there is no structure globally imposed upon them, unstructured networks are easy to build and allow for localized optimizations to different regions of the overlay. Also, because the role of all peers in the network is the same, unstructured networks are highly robust in the face of high rates of "churn"—that is, when large numbers of peers are frequently joining and leaving the network.


title: Peer-to-peer

text: However, the primary limitations of unstructured networks also arise from this lack of structure. In particular, when a peer wants to find a desired piece of data in the network, the search query must be flooded through the network to find as many peers as possible that share the data. Flooding causes a very high amount of signaling traffic in the network, uses more CPU/memory (by requiring every peer to process all search queries), and does not ensure that search queries will always be resolved. Furthermore, since there is no correlation between a peer and the content managed by it, there is no guarantee that flooding will find a peer that has the desired data. Popular content is likely to be available at several peers and any peer searching for it is likely to find the same thing. But if a peer is looking for rare data shared by only a few other peers, then it is highly unlikely that search will be successful.


title: Peer-to-peer

text: In "structured peer-to-peer networks" the overlay is organized into a specific topology, and the protocol ensures that any node can efficiently search the network for a file/resource, even if the resource is extremely rare.


title: Peer-to-peer

text: The most common type of structured P2P networks implement a distributed hash table (DHT), in which a variant of consistent hashing is used to assign ownership of each file to a particular peer. This enables peers to search for resources on the network using a hash table: that is, ("key", "value") pairs are stored in the DHT, and any participating node can efficiently retrieve the value associated with a given key.


title: Peer-to-peer

text: However, in order to route traffic efficiently through the network, nodes in a structured overlay must maintain lists of neighbors that satisfy specific criteria. This makes them less robust in networks with a high rate of "churn" (i.e. with large numbers of nodes frequently joining and leaving the network). More recent evaluation of P2P resource discovery solutions under real workloads have pointed out several issues in DHT-based solutions such as high cost of advertising/discovering resources and static and dynamic load imbalance.


title: Peer-to-peer

text: Notable distributed networks that use DHTs include Tixati, an alternative to BitTorrent's distributed tracker, the Kad network, the Storm botnet, and the YaCy. Some prominent research projects include the Chord project, Kademlia, PAST storage utility, P-Grid, a self-organized and emerging overlay network, and CoopNet content distribution system. DHT-based networks have also been widely utilized for accomplishing efficient resource discovery for grid computing systems, as it aids in resource management and scheduling of applications.


title: Peer-to-peer

text: Hybrid models are a combination of peer-to-peer and client–server models. A common hybrid model is to have a central server that helps peers find each other. Spotify was an example of a hybrid model [until 2014]. There are a variety of hybrid models, all of which make trade-offs between the centralized functionality provided by a structured server/client network and the node equality afforded by the pure peer-to-peer unstructured networks. Currently, hybrid models have better performance than either pure unstructured networks or pure structured networks because certain functions, such as searching, do require a centralized functionality but benefit from the decentralized aggregation of nodes provided by unstructured networks.


title: Peer-to-peer

text: CoopNet (Cooperative Networking) was a proposed system for off-loading serving to peers who have recently downloaded content, proposed by computer scientists Venkata N. Padmanabhan and Kunwadee Sripanidkulchai, working at Microsoft Research and Carnegie Mellon University. When a server experiences an increase in load it redirects incoming peers to other peers who have agreed to mirror the content, thus off-loading balance from the server. All of the information is retained at the server. This system makes use of the fact that the bottle-neck is most likely in the outgoing bandwidth than the CPU, hence its server-centric design. It assigns peers to other peers who are 'close in IP' to its neighbors [same prefix range] in an attempt to use locality. If multiple peers are found with the same file it designates that the node choose the fastest of its neighbors. Streaming media is transmitted by having clients cache the previous stream, and then transmit it piece-wise to new nodes.


title: Peer-to-peer

text: Like any other form of software, P2P applications can contain vulnerabilities. What makes this particularly dangerous for P2P software, however, is that peer-to-peer applications act as servers as well as clients, meaning that they can be more vulnerable to remote exploits.


title: Peer-to-peer

text: Since each node plays a role in routing traffic through the network, malicious users can perform a variety of "routing attacks", or denial of service attacks. Examples of common routing attacks include "incorrect lookup routing" whereby malicious nodes deliberately forward requests incorrectly or return false results, "incorrect routing updates" where malicious nodes corrupt the routing tables of neighboring nodes by sending them false information, and "incorrect routing network partition" where when new nodes are joining they bootstrap via a malicious node, which places the new node in a partition of the network that is populated by other malicious nodes.


title: Peer-to-peer

text: The prevalence of malware varies between different peer-to-peer protocols. Studies analyzing the spread of malware on P2P networks found, for example, that 63% of the answered download requests on the gnutella network contained some form of malware, whereas only 3% of the content on OpenFT contained malware. In both cases, the top three most common types of malware accounted for the large majority of cases (99% in gnutella, and 65% in OpenFT). Another study analyzing traffic on the Kazaa network found that 15% of the 500,000 file sample taken were infected by one or more of the 365 different computer viruses that were tested for.


title: Peer-to-peer

text: Corrupted data can also be distributed on P2P networks by modifying files that are already being shared on the network. For example, on the FastTrack network, the RIAA managed to introduce faked chunks into downloads and downloaded files (mostly MP3 files). Files infected with the RIAA virus were unusable afterwards and contained malicious code. The RIAA is also known to have uploaded fake music and movies to P2P networks in order to deter illegal file sharing. Consequently, the P2P networks of today have seen an enormous increase of their security and file verification mechanisms. Modern hashing, chunk verification and different encryption methods have made most networks resistant to almost any type of attack, even when major parts of the respective network have been replaced by faked or nonfunctional hosts.


title: Peer-to-peer

text: The decentralized nature of P2P networks increases robustness because it removes the single point of failure that can be inherent in a client–server based system. As nodes arrive and demand on the system increases, the total capacity of the system also increases, and the likelihood of failure decreases. If one peer on the network fails to function properly, the whole network is not compromised or damaged. In contrast, in a typical client–server architecture, clients share only their demands with the system, but not their resources. In this case, as more clients join the system, fewer resources are available to serve each client, and if the central server fails, the entire network is taken down.


title: Peer-to-peer

text: There are both advantages and disadvantages in P2P networks related to the topic of data backup, recovery, and availability. In a centralized network, the system administrators are the only forces controlling the availability of files being shared. If the administrators decide to no longer distribute a file, they simply have to remove it from their servers, and it will no longer be available to users. Along with leaving the users powerless in deciding what is distributed throughout the community, this makes the entire system vulnerable to threats and requests from the government and other large forces. For example, YouTube has been pressured by the RIAA, MPAA, and entertainment industry to filter out copyrighted content. Although server-client networks are able to monitor and manage content availability, they can have more stability in the availability of the content they choose to host. A client should not have trouble accessing obscure content that is being shared on a stable centralized network. P2P networks, however, are more unreliable in sharing unpopular files because sharing files in a P2P network requires that at least one node in the network has the requested data, and that node must be able to connect to the node requesting the data. This requirement is occasionally hard to meet because users may delete or stop sharing data at any point.


title: Peer-to-peer

text: In this sense, the community of users in a P2P network is completely responsible for deciding what content is available. Unpopular files will eventually disappear and become unavailable as more people stop sharing them. Popular files, however, will be highly and easily distributed. Popular files on a P2P network actually have more stability and availability than files on central networks. In a centralized network, a simple loss of connection between the server and clients is enough to cause a failure, but in P2P networks, the connections between every node must be lost in order to cause a data sharing failure. In a centralized system, the administrators are responsible for all data recovery and backups, while in P2P systems, each node requires its own backup system. Because of the lack of central authority in P2P networks, forces such as the recording industry, RIAA, MPAA, and the government are unable to delete or stop the sharing of content on P2P systems.


title: Peer-to-peer

text: In P2P networks, clients both provide and use resources. This means that unlike client–server systems, the content-serving capacity of peer-to-peer networks can actually "increase" as more users begin to access the content (especially with protocols such as Bittorrent that require users to share, refer a performance measurement study). This property is one of the major advantages of using P2P networks because it makes the setup and running costs very small for the original content distributor.


title: Peer-to-peer

text: Many peer-to-peer file sharing networks, such as Gnutella, G2, and the eDonkey network popularized peer-to-peer technologies.


title: Peer-to-peer

text: Peer-to-peer networking involves data transfer from one user to another without using an intermediate server. Companies developing P2P applications have been involved in numerous legal cases, primarily in the United States, over conflicts with copyright law. Two major cases are "Grokster vs RIAA" and "MGM Studios, Inc. v. Grokster, Ltd.". In the last case, the Court unanimously held that defendant peer-to-peer file sharing companies Grokster and Streamcast could be sued for inducing copyright infringement.


title: Peer-to-peer

text: Cooperation among a community of participants is key to the continued success of P2P systems aimed at casual human users; these reach their full potential only when large numbers of nodes contribute resources. But in current practice, P2P networks often contain large numbers of users who utilize resources shared by other nodes, but who do not share anything themselves (often referred to as the "freeloader problem"). Freeloading can have a profound impact on the network and in some cases can cause the community to collapse. In these types of networks "users have natural disincentives to cooperate because cooperation consumes their own resources and may degrade their own performance." Studying the social attributes of P2P networks is challenging due to large populations of turnover, asymmetry of interest and zero-cost identity. A variety of incentive mechanisms have been implemented to encourage or even force nodes to contribute resources.


title: Peer-to-peer

text: Some researchers have explored the benefits of enabling virtual communities to self-organize and introduce incentives for resource sharing and cooperation, arguing that the social aspect missing from today's P2P systems should be seen both as a goal and a means for self-organized virtual communities to be built and fostered. Ongoing research efforts for designing effective incentive mechanisms in P2P systems, based on principles from game theory, are beginning to take on a more psychological and information-processing direction.


title: Peer-to-peer

text: Some peer-to-peer networks (e.g. Freenet) place a heavy emphasis on privacy and anonymity—that is, ensuring that the contents of communications are hidden from eavesdroppers, and that the identities/locations of the participants are concealed. Public key cryptography can be used to provide encryption, data validation, authorization, and authentication for data/messages. Onion routing and other mix network protocols (e.g. Tarzan) can be used to provide anonymity.


title: Peer-to-peer

text: Perpetrators of live streaming sexual abuse and other cybercrimes have used peer-to-peer platforms to carry out activities with anonymity.


title: Peer-to-peer

text: Although peer-to-peer networks can be used for legitimate purposes, rights holders have targeted peer-to-peer over the involvement with sharing copyrighted material. Peer-to-peer networking involves data transfer from one user to another without using an intermediate server. Companies developing P2P applications have been involved in numerous legal cases, primarily in the United States, primarily over issues surrounding copyright law. Two major cases are "Grokster vs RIAA" and "MGM Studios, Inc. v. Grokster, Ltd." In both of the cases the file sharing technology was ruled to be legal as long as the developers had no ability to prevent the sharing of the copyrighted material. To establish criminal liability for the copyright infringement on peer-to-peer systems, the government must prove that the defendant infringed a copyright willingly for the purpose of personal financial gain or commercial advantage. Fair use exceptions allow limited use of copyrighted material to be downloaded without acquiring permission from the rights holders. These documents are usually news reporting or under the lines of research and scholarly work. Controversies have developed over the concern of illegitimate use of peer-to-peer networks regarding public safety and national security. When a file is downloaded through a peer-to-peer network, it is impossible to know who created the file or what users are connected to the network at a given time. Trustworthiness of sources is a potential security threat that can be seen with peer-to-peer systems.


title: Peer-to-peer

text: A study ordered by the European Union found that illegal downloading "may" lead to an increase in overall video game sales because newer games charge for extra features or levels. The paper concluded that piracy had a negative financial impact on movies, music, and literature. The study relied on self-reported data about game purchases and use of illegal download sites. Pains were taken to remove effects of false and misremembered responses.


title: Peer-to-peer

text: Peer-to-peer applications present one of the core issues in the network neutrality controversy. Internet service providers (ISPs) have been known to throttle P2P file-sharing traffic due to its high-bandwidth usage. Compared to Web browsing, e-mail or many other uses of the internet, where data is only transferred in short intervals and relative small quantities, P2P file-sharing often consists of relatively heavy bandwidth usage due to ongoing file transfers and swarm/network coordination packets. In October 2007, Comcast, one of the largest broadband Internet providers in the United States, started blocking P2P applications such as BitTorrent. Their rationale was that P2P is mostly used to share illegal content, and their infrastructure is not designed for continuous, high-bandwidth traffic. Critics point out that P2P networking has legitimate legal uses, and that this is another way that large providers are trying to control use and content on the Internet, and direct people towards a client–server-based application architecture. The client–server model provides financial barriers-to-entry to small publishers and individuals, and can be less efficient for sharing large files. As a reaction to this bandwidth throttling, several P2P applications started implementing protocol obfuscation, such as the BitTorrent protocol encryption. Techniques for achieving "protocol obfuscation" involves removing otherwise easily identifiable properties of protocols, such as deterministic byte sequences and packet sizes, by making the data look as if it were random. The ISP's solution to the high bandwidth is P2P caching, where an ISP stores the part of files most accessed by P2P clients in order to save access to the Internet.


title: Peer-to-peer

text: Researchers have used computer simulations to aid in understanding and evaluating the complex behaviors of individuals within the network. "Networking research often relies on simulation in order to test and evaluate new ideas. An important requirement of this process is that results must be reproducible so that other researchers can replicate, validate, and extend existing work." If the research cannot be reproduced, then the opportunity for further research is hindered. "Even though new simulators continue to be released, the research community tends towards only a handful of open-source simulators. The demand for features in simulators, as shown by our criteria and survey, is high. Therefore, the community should work together to get these features in open-source software. This would reduce the need for custom simulators, and hence increase repeatability and reputability of experiments."


title: Peer-to-peer

text: Besides all the above stated facts, there has also been work done on ns-2 open source network simulators. One research issue related to free rider detection and punishment has been explored using ns-2 simulator here.


title: Cody Gakpo

text: Cody Mathès Gakpo (; born 7 May 1999) is a Dutch professional footballer who plays as a winger for Eredivisie club PSV and the Netherlands national team.


title: Cody Gakpo

text: A PSV academy graduate, Gakpo made his first-team debut for the club in February 2018. In the 2021–22 season, he won the Dutch Footballer of the Year award after scoring 21 goals in 47 games in all competitions.


title: Cody Gakpo

text: Gakpo played youth international football for the Netherlands from under-18 to under-21 level. He made his senior international debut in June 2021 at Euro 2020.


title: Cody Gakpo

text: Gakpo was born in Eindhoven and raised in the district of Stratum. His father was born in Togo and has Ghanaian ancestry, while his mother is Dutch. In 2007, he moved to the youth academy of PSV, where he then progressed through all of the youth teams.


title: Cody Gakpo

text: For the 2016–17 season Gakpo was part of the reserve team Jong PSV for the first time, but mainly featured in the U19 team. Gakpo made his professional debut in the Eerste Divisie for Jong PSV on 4 November 2016 in a game against Helmond Sport. In the rest of the season he only made one more appearance for Jong PSV. After his production increased in the following season's U19 Eredivisie with seven goals and five assists in 13 league games, he was finally promoted to the reserves at the turn of the year. In his second appearance in the second-tier Eerste Divisie, on 19 January 2017 in a 3–2 away win against De Graafschap, he scored a brace and made the assist for the third goal of his team. For Jong PSV, he managed to score seven goals in the 2017–18 season, which he achieved in 12 league games.


title: Cody Gakpo

text: Gakpo made his first team debut for PSV as an injury-time substitute in a 3–1 victory over Feyenoord on 25 February 2018. In the 2018–19 season, Gakpo was able to further improve his performances. This was also noticed by first team coach, Mark van Bommel. He was selected several times for the matchday squad of the first team in the first half of the season. He would initially, however, remain an unused substitute. In the 5–1 home win against the Go Ahead Eagles on 3 December 2018, he scored the first hat-trick of his professional career. After he scored a goal and got an assist in the 5–2 home win against Almere City on 21 December, he made his debut in the Eredivisie just one day later. In the 3–1 home win against AZ, he was substituted on for Steven Bergwijn in the closing stages. He scored nine goals in ten league games for Jong PSV by the end of the year and was subsequently promoted to become a regular member of the first team. On 3 February 2019, he scored his first league goal in his second appearance in a 5–0 home win over Fortuna Sittard and also assisted another goal. By the end of the season he made 14 league appearances, but without being able to record another goal.


title: Cody Gakpo

text: In the 2019–20 season, he made his breakthrough in the Eredivisie and recorded seven goals and as many assists in 25 league games.


title: Cody Gakpo

text: On 13 September 2020, the first matchday of the 2020–21 Eredivisie season, Gakpo scored his first brace for PSV, contributing to a 3–1 win over Groningen. He scored another brace on 24 September in the 5–1 victory in the UEFA Europa League qualifier against NŠ Mura, allowing PSV to qualify for the play-off round. He was again decisive there, on scoring PSV's second goal in a 2–0 win over Rosenborg on 1 October. He finished the season with 29 appearances, in which he scored 11 goals.


title: Cody Gakpo

text: Gakpo scored the winning goal for PSV in a 2–1 win over Ajax in the 2022 KNVB Cup Final. On 31 August 2022, he scored his first hat-trick in a 7–1 win over Volendam.


title: Cody Gakpo

text: Despite rumours of interest from Manchester United, Leeds United and Southampton during the 2022 summer transfer window, Gakpo remained at PSV for the 2022–23 season.


title: Cody Gakpo

text: Gakpo was eligible to play for the Netherlands, Ghana or Togo at international level. He played youth international football for the Netherlands at under-18, under-19, under-20 and under-21 levels.


title: Cody Gakpo

text: Gakpo was called up to the senior Netherlands squad for UEFA Euro 2020 and made his debut in the third match of the group stage against North Macedonia as a substitute in the 79th minute for Frenkie de Jong. Thereby, he became the first Netherlands player to make his international debut at a European Championship since Martien Vreijsen in 1980.


title: Cody Gakpo

text: He was named to the 2022 World Cup squad and had an immediate impact, scoring in three consecutive Group A matches against Senegal, Ecuador, and Qatar.


title: Cody Gakpo

text: Usually deployed on the left wing, Gakpo often cuts inside on his right foot to move to a more central attacking position, and uses his speed and dribbling skills to take on defenders until he finds the space to make an attempt on goal.


title: Psilocybe cubensis

text: Psilocybe cubensis is a species of psychedelic mushroom whose principal active compounds are psilocybin and psilocin. Commonly called shrooms, magic mushrooms, golden halos, cubes, or gold caps, it belongs to the fungus family Hymenogastraceae and was previously known as Stropharia cubensis. It is the best-known psilocybin mushroom due to its wide distribution and ease of cultivation.


title: Psilocybe cubensis

text: The species was first described in 1906 as "Stropharia cubensis" by American mycologist Franklin Sumner Earle in Cuba. In 1907, it was identified as "Naematoloma caerulescens" in Tonkin (now northern Vietnam) by French pharmacist and mycologist Narcisse Théophile Patouillard, while in 1941, it was called "Stropharia cyanescens" by William Alphonso Murrill near Gainesville in Florida. German-born mycologist Rolf Singer moved the species into the genus "Psilocybe" in 1949, giving it the binomial name "Psilocybe cubensis". The synonyms were later also assigned to the species "Psilocybe cubensis".


title: Psilocybe cubensis

text: The name " Psilocybe " is derived from the Ancient Greek roots "psilos" (ψιλος) and "kubê" (κυβη), and translates as "bare head". "Cubensis" means "coming from Cuba", and refers to the type locality published by Earle.


title: Psilocybe cubensis

text: Singer divided "P. cubensis" into three varieties: the nominate, which usually had a brownish cap, Murrill's "cyanescens" from Florida, which generally had a pale cap, and var "caerulascens" from Indochina with a more yellowish cap.


title: Psilocybe cubensis

text: "Psilocybe cubensis" is commonly known as gold top, golden top or gold cap in Australia, sacred mushroom or blue mushroom in Brazil, and San Ysidro or Palenque mushroom in the United States and Mexico, while the term "magic mushroom" has been applied to hallucinogenic mushrooms in general. A common name in Thai is "Hed keequai", which translates as "mushroom which appears after water buffalo defecates".


title: Psilocybe cubensis

text: The cap is , conic to convex with a central papilla when young, becoming broadly convex to plane with age, retaining a slight umbo sometimes surrounded by a ring-shaped depression. The cap surface is smooth and sticky, sometimes with white universal veil remnants attached. The cap is brown becoming paler to almost white at the margin and fades to more golden-brown or yellowish with age. When bruised, all parts of the mushroom stain blue. The narrow grey gills are adnate to adnexed, sometimes seceding attachment, and darken to purplish-black and somewhat mottled with age. The gill edges remain whitish. The hollow white stipe is high by thick, becoming yellowish in age. The well-developed veil leaves a persistent white membranous ring whose surface usually becomes the same color as the gills because of falling spores. The fruiting bodies are 90% water. The mushroom has no odor and has been described as tasting farinaceous, with an alkaline or metallic aftertaste. The spores are 11.5–17.3 x 8–11.5 µm, sub-ellipsoid, basidia 4-spored but sometimes 2- or 3-, pleurocystidia and cheilocystidia present.


title: Psilocybe cubensis

text: The related species "Psilocybe subcubensis"—found in tropical regions—is indistinguishable but has smaller spores.


title: Psilocybe cubensis

text: "Psilocybe cubensis" is a pan-tropical species, occurring in the Gulf Coast states and southeastern United States, Mexico, in the Central American countries of Belize, Costa Rica, and Guatemala, the Caribbean countries Cuba, the Dominican Republic, Guadalupe, Martinique, and Trinidad, in the South American countries of Argentina, Bolivia, Brazil, Colombia, French Guiana, Paraguay, Uruguay and Peru, Southeast Asia, including Thailand, Vietnam, Cambodia and Malaysia, India, Australia (including Tasmania), New Zealand, Fiji, and possibly Nepal and Hawaii.


title: Psilocybe cubensis

text: "Psilocybe cubensis" is found on cow (and occasionally horse) dung, sugar cane mulch or rich pasture soil, with mushrooms appearing from February to December in the northern hemisphere, and November to April in the southern hemisphere. In Asia, the species grows on water buffalo dung. Along with other fungi that grow on cow dung, "P. cubensis" is thought to have colonized Australia with the introduction of cattle there, 1800 of which were on the Australian mainland by 1803—having been transported there from the Cape of Good Hope, Kolkata and the American west coast. In Australia, the species grows between northern Queensland to southern New South Wales.


title: Psilocybe cubensis

text: In March 2018, several "Psilocybe cubensis" specimens were collected in Zimbabwe in the Wedza District of Mashonaland East province, approx. 120 km southeast of Harare. This was the first reported occurrence of a psilocybin mushroom in Zimbabwe. The mushrooms were collected on Imire Rhino & Wildlife Conservation - a nature reserve that is home to both wildlife and cattle, as well as cattle egrets.


title: Psilocybe cubensis

text: In a 1992 paper, locals and tourists in Thailand were reported to consume "P. cubensis" and related species in mushroom omelets—particularly in Ko Samui and Ko Pha-ngan. At times, omelets were adulterated with LSD, resulting in prolonged intoxication. A thriving subculture had developed in the region. Other localities, such as Hat Yai, Ko Samet, and Chiang Mai, also had some reported usage.


title: Psilocybe cubensis

text: In 1996, jars of honey containing Psilocybe cubensis were confiscated at the Dutch-German border. Upon examination, it was revealed that jars of honey containing psychedelic mushrooms were being sold at Dutch coffee shops.


title: Psilocybe cubensis

text: "P. cubensis" is probably the most widely known of the psilocybin-containing mushrooms used for triggering psychedelic experiences after ingestion.


title: Psilocybe cubensis

text: The concentrations of psilocin and psilocybin, as determined by high-performance liquid chromatography, are in the range of 0.14–0.42% (wet weight) and 0.37–1.30% (dry weight) in the whole mushroom, 0.17–0.78% (wet weight) and 0.44–1.35% (dry weight) in the cap, and 0.09%–0.30% (wet weight) and 0.05–1.27% (dry weight) in the stem, respectively. For quickly and practically measuring the psychoactive contents of most healthy Psilocybe cubensis varieties, it can generally be assumed that there is approximately 15mg (+/- 5mg) of psilocybin per gram of dried mushroom. Furthermore, due to factors such as age and storage method, the psilocybin and psilocin content of a given sample of mushrooms will vary.


title: Psilocybe cubensis

text: Individual brain chemistry and psychological predisposition play a significant role in determining appropriate doses. For a modest psychedelic effect, a minimum of one gram of dried "Psilocybe cubensis" mushrooms is ingested orally, 0.25–1 gram is usually sufficient to produce a mild effect, 1–2.5 grams usually provides a moderate effect, and 2.5 grams and higher usually produces strong effects. For most people, 3.5 dried grams (1/8 oz) would be considered a high dose and may produce an intense experience; this is, however, typically considered a standard dose among recreational users. For many individuals, doses above three grams may be overwhelming. For a few rare people, doses as small as 0.25 gram can produce full-blown effects normally associated with very high doses. For most people, however, that dose level would result in virtually no effects.


title: Psilocybe cubensis

text: There are many different ways to ingest Psilocybe cubensis. Consumers may prefer to take them raw, either freshly harvested or dried and preserved. It is also possible to prepare culinary dishes with the mushrooms such as pasta or tea. However the psychoactive compounds begin to break down rapidly at temperatures exceeding 100°C (212°F). Another method of ingestion known as "Lemon Tekking" involves combining pulverized Psilocybe cubensis with a concentrated citrus juice with a pH of ~2. After approximately 20 minutes, a considerable amount of the psilocybin will have been dephosphorylated into psilocin, the psychoactive tryptamine. This method of consumption results in a more rapid onset, and can potentially offer easier digestion, or reduced "come-up pressure" associated with raw consumption. Psilocybin cubensis can also be taken in conjunction with other botanicals such as turmeric, ginger, and black pepper. A 2019 study observed turmeric to act as a mild MAOI, which when combined with psilocin, potentiates the biochemical interactions between serotonin receptors and psilocin creating an entourage effect.


title: Psilocybe cubensis

text: Upon ingestion, effects usually begin after approximately 20–60 minutes (depending on the method of ingestion and stomach contents) and may last from four to ten hours, depending on dosage and individual biochemistry. Visual distortions often occur, including walls that seem to breathe, a vivid enhancement of colors and the animation of organic shapes.


title: Psilocybe cubensis

text: The effects of very high doses can be overwhelming depending on the particular phenotype of cubensis, grow method, and the individual. It is recommended not to eat wild mushrooms without properly identifying them as they may be poisonous. In particular, similar species include mushrooms of the genus "Galerina" and "Pholiotina rugosa"—all potentially deadly—and "Chlorophyllum molybdites". All of these grow in pastures—similar habitat to that preferred by "P. cubensis".


title: Psilocybe cubensis

text: In 2019, a 15-year-old boy suffered from transient kidney failure after eating "P. cubensis" from a cultivation kit in Canada. No one else in the group suffered any ill effects.


title: Psilocybe cubensis

text: Within the sub-strains of Psilocybe Cubensis, the Penis Envy strain tends to contain much more Psilocybin and Psilocin when compared to other Cubensis mushrooms.


title: Psilocybe cubensis

text: Psilocybin and psilocin are listed as Schedule I drugs under the United Nations 1971 Convention on Psychotropic Substances. However, mushrooms containing psilocybin and psilocin are not illegal in some parts of the world. For example, in Brazil they are legal, but extractions from the mushroom containing psilocybin and psilocin remain illegal. In the United States, growing or possessing "Psilocybe cubensis" mushrooms is illegal in all states, but it is legal to possess and buy the spores for microscopy purposes. However, as of May 8, 2019 Denver, Colorado has decriminalized it for those 21 and up. On June 4, 2019, Oakland, California followed suit, decriminalizing psilocybin-containing mushrooms as well as the Peyote cactus. On January 29, 2020, Santa Cruz, California decriminalized naturally-occurring psychedelics, including psilocybin mushrooms. On November 3, 2020, the state of Oregon decriminalized possession of psilocybin mushrooms for recreational use and granted licensed practitioners permission to administer psilocybin mushrooms to individuals age 21 years and older.


title: Psilocybe cubensis

text: In 1978, the Florida Supreme Court ruled in "Fiske vs Florida" that possession of psilocybin mushrooms is not illegal, in that the mushrooms cannot be considered a "container" for psilocybin based on how the law is written, i.e., it does not specifically state that psilocybin mushrooms themselves are illegal, but that the hallucinogenic constituents in them are. According to this decision, the applicable statute as framed imparts no information as to which plants may contain psilocybin in its natural state and does not advise a person of ordinary intelligence that this substance is contained in a particular variety of mushroom. The statute, therefore, can not constitutionally be applied to the appellant.


title: Psilocybe cubensis

text: Psilocybe cubensis grows naturally in tropical and subtropical conditions, often near cattle due to the ideal conditions they provide for the growth of the fungus. The cow usually consumes grains or grass covered with the spores of Psilocybe cubensis and the fungus will begin to germinate within the dung.


title: Psilocybe cubensis

text: Mushrooms such as Psilocybe cubensis are relatively easy to cultivate indoors. First, spores are inoculated within sterilized jars or bags, colloquially known as grainspawn, containing a form of carbohydrate nutrient such as rye grains. After approximately one month, the spores fully colonize the grain spawn forming dense mycelium, which is then planted within a substrate such as a coconut husk fiber and vermiculite mixture. Given proper humidity, temperature, and fresh air exchange, the substrate will produce fruiting Psilocybe cubensis bodies within a month of planting. To preserve the potency after harvesting, growers often dehydrate the fruit and store them within air-tight containers in dark, cool environments.


title: Psilocybe cubensis

text: A study conducted in 2009 showed that mushrooms grown in the dark had higher levels of psilocybin and psilocin compared to the mushrooms grown in bright, indirect light which had minimum levels.


title: Psilocybe cubensis

text: Studies were conducted where an environmentally controlled wind tunnel and a computer program were used to determine the influence of humidity on the individual basidiocarps of Psilocybe cubensis which aided in mapping their growth and development. The transpiration and growth of the mushroom was heavily influenced due to the humidity of the air and the transpiration was accelerated at higher humidities while light had no effect on the growth. Faster growth was observed at higher humidities. It was also discovered that misting enhanced both the growth and transpiration rates in the growing process of Psilocybe cubensis.


title: Psilocybe cubensis

text: Personal-scale cultivation of "Psilocybe cubensis" mushrooms ranges from the relatively simple and small-scale PF Tek and other "cake" methods, that produce a limited amount of mushrooms, to advanced techniques utilizing methods of professional mushroom cultivators. These advanced methods require a greater investment of time, money, and knowledge, but reward the diligent cultivator with far larger and much more consistent harvests.


title: Psilocybe cubensis

text: Terence and Dennis McKenna made "Psilocybe cubensis" particularly famous when they published "Psilocybin: Magic Mushroom Grower's Guide" in the 1970s upon their return from the Amazon rainforest, having deduced new methods (based on pre-existing techniques originally described by J.P. San Antonio) for growing psilocybin mushrooms and assuring their audience that "Psilocybe cubensis" were amongst the easiest psilocybin-containing mushrooms to cultivate.


title: Psilocybe cubensis

text: The potency of cultivated specimens can vary widely in accordance with each flush (harvest). In a classic paper published by Jeremy Bigwood and M.W. Beug, it was shown that with each flush, psilocybin levels varied somewhat unpredictably but were much the same on the first flush as they were on the last flush; however, psilocin was typically absent in the first two flushes but peaked by the fourth flush, making it the most potent. Two strains were also analyzed to determine potency in caps and stems: In one strain the caps contained generally twice as much psilocybin as the stems, but the small amount of psilocin present was entirely in the stems. In the other strain, a trace of psilocin was present in the cap but not in the stem; the cap and stem contained equal amounts of psilocybin. The study concluded that the levels of psilocybin and psilocin vary by over a factor of four in cultures of "Psilocybe cubensis" grown under controlled conditions.


title: Psilocybe cubensis

text: Because "Psilocybe cubensis" is intimately associated with cattle ranching, the fungus has found unique dispersal niches not available to most other members of the family Hymenogastraceae. Of particular interest is the cattle egret ("Bubulcus ibis"), a colonizer of Old World origin (via S. America), whose range of distribution overlaps much of that of "Psilocybe cubensis." Cattle egrets typically walk alongside cattle, preying on insects; they track through spore-laden vegetation and cow dung and transfer the spores to suitable habitats, often thousands of miles away during migration activities. This type of spore dispersal is known as zoochory, and it enables a parent species to propagate over a much greater range than it could achieve alone. The relationship between cattle, cattle egrets, and "Psilocybe cubensis" is an example of symbiosis—a situation in which dissimilar organisms live together in close association.


title: Psilocybe cubensis

text: One case of "Psilocybe cubensis"-induced fungemia has been reported, in which a 30-year-old individual prepared then injected mushroom tea filtered through a cotton swab intravenously, which proceeded to develop into an array of symptoms at the start, such as jaundice, diarrhea, nausea, and hematemesis. After being admitted to the hospital, the examination revealed that the individual was suffering from multiple organ failure due to a bacterial (Brevibacillus) and fungal (Psilocybe cubensis) infection.


title: Acetylcholine

text: Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Parts in the body that use or are affected by acetylcholine are referred to as cholinergic. Substances that increase or decrease the overall activity of the cholinergic system are called cholinergics and anticholinergics, respectively.


title: Acetylcholine

text: Acetylcholine is the neurotransmitter used at the neuromuscular junction—in other words, it is the chemical that motor neurons of the nervous system release in order to activate muscles. This property means that drugs that affect cholinergic systems can have very dangerous effects ranging from paralysis to convulsions. Acetylcholine is also a neurotransmitter in the autonomic nervous system, both as an internal transmitter for the sympathetic nervous system and as the final product released by the parasympathetic nervous system. Acetylcholine is the primary neurotransmitter of the parasympathetic nervous system.


title: Acetylcholine

text: In the brain, acetylcholine functions as a neurotransmitter and as a neuromodulator. The brain contains a number of cholinergic areas, each with distinct functions; such as playing an important role in arousal, attention, memory and motivation.


title: Acetylcholine

text: Acetylcholine has also been found in cells of non-neural origins as well as microbes. Recently, enzymes related to its synthesis, degradation and cellular uptake have been traced back to early origins of unicellular eukaryotes. The protist pathogen "Acanthamoeba" spp. has shown evidence of the presence of ACh, which provides growth and proliferative signals via a membrane located M1-muscarinic receptor homolog.


title: Acetylcholine

text: Partly because of its muscle-activating function, but also because of its functions in the autonomic nervous system and brain, many important drugs exert their effects by altering cholinergic transmission. Numerous venoms and toxins produced by plants, animals, and bacteria, as well as chemical nerve agents such as Sarin, cause harm by inactivating or hyperactivating muscles through their influences on the neuromuscular junction. Drugs that act on muscarinic acetylcholine receptors, such as atropine, can be poisonous in large quantities, but in smaller doses they are commonly used to treat certain heart conditions and eye problems. Scopolamine, which acts mainly on muscarinic receptors in the brain, can cause delirium, hallucinations, and amnesia. The addictive qualities of nicotine are derived from its effects on nicotinic acetylcholine receptors in the brain.


title: Acetylcholine

text: Acetylcholine is a choline molecule that has been acetylated at the oxygen atom. Because of the charged ammonium group, acetylcholine does not penetrate lipid membranes. Because of this, when the molecule is introduced externally, it remains in the extracellular space and at present it is considered that the molecule does not pass through the blood–brain barrier.


title: Acetylcholine

text: Acetylcholine is synthesized in certain neurons by the enzyme choline acetyltransferase from the compounds choline and acetyl-CoA. Cholinergic neurons are capable of producing ACh. An example of a central cholinergic area is the nucleus basalis of Meynert in the basal forebrain.


title: Acetylcholine

text: The enzyme acetylcholinesterase converts acetylcholine into the inactive metabolites choline and acetate. This enzyme is abundant in the synaptic cleft, and its role in rapidly clearing free acetylcholine from the synapse is essential for proper muscle function. Certain neurotoxins work by inhibiting acetylcholinesterase, thus leading to excess acetylcholine at the neuromuscular junction, causing paralysis of the muscles needed for breathing and stopping the beating of the heart.


title: Acetylcholine

text: Acetylcholine functions in both the central nervous system (CNS) and the peripheral nervous system (PNS). In the CNS, cholinergic projections from the basal forebrain to the cerebral cortex and hippocampus support the cognitive functions of those target areas. In the PNS, acetylcholine activates muscles and is a major neurotransmitter in the autonomic nervous system.


title: Acetylcholine

text: Like many other biologically active substances, acetylcholine exerts its effects by binding to and activating receptors located on the surface of cells. There are two main classes of acetylcholine receptor, nicotinic and muscarinic. They are named for chemicals that can selectively activate each type of receptor without activating the other: muscarine is a compound found in the mushroom "Amanita muscaria"; nicotine is found in tobacco.


title: Acetylcholine

text: Nicotinic acetylcholine receptors are ligand-gated ion channels permeable to sodium, potassium, and calcium ions. In other words, they are ion channels embedded in cell membranes, capable of switching from a closed to an open state when acetylcholine binds to them; in the open state they allow ions to pass through. Nicotinic receptors come in two main types, known as muscle-type and neuronal-type. The muscle-type can be selectively blocked by curare, the neuronal-type by hexamethonium. The main location of muscle-type receptors is on muscle cells, as described in more detail below. Neuronal-type receptors are located in autonomic ganglia (both sympathetic and parasympathetic), and in the central nervous system.


title: Acetylcholine

text: Muscarinic acetylcholine receptors have a more complex mechanism, and affect target cells over a longer time frame. In mammals, five subtypes of muscarinic receptors have been identified, labeled M1 through M5. All of them function as G protein-coupled receptors, meaning that they exert their effects via a second messenger system. The M1, M3, and M5 subtypes are G-coupled; they increase intracellular levels of IP and calcium by activating phospholipase C. Their effect on target cells is usually excitatory. The M2 and M4 subtypes are G/G-coupled; they decrease intracellular levels of cAMP by inhibiting adenylate cyclase. Their effect on target cells is usually inhibitory. Muscarinic acetylcholine receptors are found in both the central nervous system and the peripheral nervous system of the heart, lungs, upper gastrointestinal tract, and sweat glands.


title: Acetylcholine

text: Acetylcholine is the substance the nervous system uses to activate skeletal muscles, a kind of striated muscle. These are the muscles used for all types of voluntary movement, in contrast to smooth muscle tissue, which is involved in a range of involuntary activities such as movement of food through the gastrointestinal tract and constriction of blood vessels. Skeletal muscles are directly controlled by motor neurons located in the spinal cord or, in a few cases, the brainstem. These motor neurons send their axons through motor nerves, from which they emerge to connect to muscle fibers at a special type of synapse called the neuromuscular junction.


title: Acetylcholine

text: When a motor neuron generates an action potential, it travels rapidly along the nerve until it reaches the neuromuscular junction, where it initiates an electrochemical process that causes acetylcholine to be released into the space between the presynaptic terminal and the muscle fiber. The acetylcholine molecules then bind to nicotinic ion-channel receptors on the muscle cell membrane, causing the ion channels to open. Sodium ions then flow into the muscle cell, initiating a sequence of steps that finally produce muscle contraction.


title: Acetylcholine

text: Calcium channel blockers (nifedipine, diltiazem) do not affect P-channels. These drugs affect L-type calcium channels.


title: Acetylcholine

text: The autonomic nervous system controls a wide range of involuntary and unconscious body functions. Its main branches are the sympathetic nervous system and parasympathetic nervous system. Broadly speaking, the function of the sympathetic nervous system is to mobilize the body for action; the phrase often invoked to describe it is fight-or-flight. The function of the parasympathetic nervous system is to put the body in a state conducive to rest, regeneration, digestion, and reproduction; the phrase often invoked to describe it is "rest and digest" or "feed and breed". Both of these aforementioned systems use acetylcholine, but in different ways.


title: Acetylcholine

text: At a schematic level, the sympathetic and parasympathetic nervous systems are both organized in essentially the same way: preganglionic neurons in the central nervous system send projections to neurons located in autonomic ganglia, which send output projections to virtually every tissue of the body. In both branches the internal connections, the projections from the central nervous system to the autonomic ganglia, use acetylcholine as a neurotransmitter to innervate (or excite) ganglia neurons. In the parasympathetic nervous system the output connections, the projections from ganglion neurons to tissues that don't belong to the nervous system, also release acetylcholine but act on muscarinic receptors. In the sympathetic nervous system the output connections mainly release noradrenaline, although acetylcholine is released at a few points, such as the sudomotor innervation of the sweat glands.


title: Acetylcholine

text: Acetylcholine in the serum exerts a direct effect on vascular tone by binding to muscarinic receptors present on vascular endothelium. These cells respond by increasing production of nitric oxide, which signals the surrounding smooth muscle to relax, leading to vasodilation.


title: Acetylcholine

text: In the central nervous system, ACh has a variety of effects on plasticity, arousal and reward. ACh has an important role in the enhancement of alertness when we wake up, in sustaining attention and in learning and memory.


title: Acetylcholine

text: Damage to the cholinergic (acetylcholine-producing) system in the brain has been shown to be associated with the memory deficits associated with Alzheimer's disease. ACh has also been shown to promote REM sleep.


title: Acetylcholine

text: In the brainstem acetylcholine originates from the Pedunculopontine nucleus and laterodorsal tegmental nucleus collectively known as the mesopontine tegmentum area or pontomesencephalotegmental complex. In the basal forebrain, it originates from the basal nucleus of Meynert and medial septal nucleus:


title: Acetylcholine

text: In addition, ACh acts as an important internal transmitter in the striatum, which is part of the basal ganglia. It is released by cholinergic interneurons. In humans, non-human primates and rodents, these interneurons respond to salient environmental stimuli with responses that are temporally aligned with the responses of dopaminergic neurons of the substantia nigra.


title: Acetylcholine

text: Acetylcholine has been implicated in learning and memory in several ways. The anticholinergic drug, scopolamine, impairs acquisition of new information in humans and animals. In animals, disruption of the supply of acetylcholine to the neocortex impairs the learning of simple discrimination tasks, comparable to the acquisition of factual information and disruption of the supply of acetylcholine to the hippocampus and adjacent cortical areas produces forgetfulness, comparable to anterograde amnesia in humans.


title: Acetylcholine

text: The disease myasthenia gravis, characterized by muscle weakness and fatigue, occurs when the body inappropriately produces antibodies against acetylcholine nicotinic receptors, and thus inhibits proper acetylcholine signal transmission. Over time, the motor end plate is destroyed. Drugs that competitively inhibit acetylcholinesterase (e.g., neostigmine, physostigmine, or primarily pyridostigmine) are effective in treating the symptoms of this disorder. They allow endogenously released acetylcholine more time to interact with its respective receptor before being inactivated by acetylcholinesterase in the synaptic cleft (the space between nerve and muscle).


title: Acetylcholine

text: Blocking, hindering or mimicking the action of acetylcholine has many uses in medicine. Drugs acting on the acetylcholine system are either agonists to the receptors, stimulating the system, or antagonists, inhibiting it. Acetylcholine receptor agonists and antagonists can either have an effect directly on the receptors or exert their effects indirectly, e.g., by affecting the enzyme acetylcholinesterase, which degrades the receptor ligand. Agonists increase the level of receptor activation; antagonists reduce it.


title: Acetylcholine

text: Acetylcholine itself does not have therapeutic value as a drug for intravenous administration because of its multi-faceted action (non-selective) and rapid inactivation by cholinesterase. However, it is used in the form of eye drops to cause constriction of the pupil during cataract surgery, which facilitates quick post-operational recovery.


title: Acetylcholine

text: Nicotine binds to and activates nicotinic acetylcholine receptors, mimicking the effect of acetylcholine at these receptors. ACh opens a Na channel upon binding so that Na flows into the cell. This causes a depolarization, and results in an excitatory post-synaptic potential. Thus, ACh is excitatory on skeletal muscle; the electrical response is fast and short-lived. Curares are arrow poisons, which act at nicotinic receptors and have been used to develop clinically useful therapies.


title: Acetylcholine

text: Muscarinic receptors form G protein-coupled receptor complexes in the cell membranes of neurons and other cells. Atropine is a non-selective competitive antagonist with Acetylcholine at muscarinic receptors.


title: Acetylcholine

text: Many ACh receptor agonists work indirectly by inhibiting the enzyme acetylcholinesterase. The resulting accumulation of acetylcholine causes continuous stimulation of the muscles, glands, and central nervous system, which can result in fatal convulsions if the dose is high.


title: Acetylcholine

text: They are examples of enzyme inhibitors, and increase the action of acetylcholine by delaying its degradation; some have been used as nerve agents (Sarin and VX nerve gas) or pesticides (organophosphates and the carbamates). Many toxins and venoms produced by plants and animals also contain cholinesterase inhibitors. In clinical use, they are administered in low doses to reverse the action of muscle relaxants, to treat myasthenia gravis, and to treat symptoms of Alzheimer's disease (rivastigmine, which increases cholinergic activity in the brain).


title: Acetylcholine

text: Organic mercurial compounds, such as methylmercury, have a high affinity for sulfhydryl groups, which causes dysfunction of the enzyme choline acetyltransferase. This inhibition may lead to acetylcholine deficiency, and can have consequences on motor function.


title: Acetylcholine

text: Botulinum toxin (Botox) acts by suppressing the release of acetylcholine, whereas the venom from a black widow spider (alpha-latrotoxin) has the reverse effect. ACh inhibition causes paralysis. When bitten by a black widow spider, one experiences the wastage of ACh supplies and the muscles begin to contract. If and when the supply is depleted, paralysis occurs.


title: Acetylcholine

text: Acetylcholine is used by organisms in all domains of life for a variety of purposes. It is believed that choline, a precursor to acetylcholine, was used by single celled organisms billions of years ago for synthesizing cell membrane phospholipids. Following the evolution of choline transporters, the abundance of intracellular choline paved the way for choline to become incorporated into other synthetic pathways, including acetylcholine production. Acetylcholine is used by bacteria, fungi, and a variety of other animals. Many of the uses of acetylcholine rely on its action on ion channels via GPCRs like membrane proteins.


title: Acetylcholine

text: The two major types of acetylcholine receptors, muscarinic and nicotinic receptors, have convergently evolved to be responsive to acetylcholine. This means that rather than having evolved from a common homolog, these receptors evolved from separate receptor families. It is estimated that the nicotinic receptor family dates back longer than 2.5 billion years. Likewise, muscarinic receptors are thought to have diverged from other GPCRs at least 0.5 billion years ago. Both of these receptor groups have evolved numerous subtypes with unique ligand affinities and signaling mechanisms. The diversity of the receptor types enables acetylcholine to create varying responses depending on which receptor types are activated, and allow for acetylcholine to dynamically regulate physiological processes. ACh receptors are related to 5-HT3 (serotonin), GABA, and Glycine receptors, both in sequence and structure, strongly suggesting that they have a common evolutionary origin.


title: Acetylcholine

text: In 1867, Adolf von Baeyer resolved the structures of choline and acetylcholine and synthetized them both, referring to the latter as ""acetylneurin"" in the study. Choline is a precursor for acetylcholine. This is why Frederick Walker Mott and William Dobinson Halliburton noted in 1899 that choline injections decreased the blood pressure of animals. Acetylcholine was first noted to be biologically active in 1906, when Reid Hunt (1870–1948) and René de M. Taveau found that it decreased blood pressure in exceptionally tiny doses.


title: Acetylcholine

text: In 1914, Arthur J. Ewins was the first to extract acetylcholine from nature. He identified it as the blood pressure decreasing contaminant from some "Claviceps purpurea" ergot extracts, by the request of Henry Hallett Dale. Later in 1914, Dale outlined the effects of acetylcholine at various types of peripheral synapses and also noted that it lowered the blood pressure of cats via subcutaneous injections even at doses of one nanogram.


title: Acetylcholine

text: The concept of neurotransmitters was unknown until 1921, when Otto Loewi noted that the vagus nerve secreted a substance that inhibited the heart muscle whilst working as a professor in the University of Graz. He named it "vagusstoff" ("vagus substance"), noted it to be a structural analog of choline and suspected it to be acetylcholine. In 1926, Loewi and E. Navratil deduced that the compound is probably acetylcholine, as vagusstoff and synthetic acetylcholine lost their activity in a similar manner when in contact with tissue lysates that contained acetylcholine-degrading enzymes (now known to be cholinesterases). This conclusion was accepted widely. Later studies confirmed the function of acetylcholine as a neurotransmitter.


title: Acetylcholine

text: In 1936, H. H. Dale and O. Loewi shared the Nobel Prize in Physiology or Medicine for their studies of acetylcholine and nerve impulses.


title: Philip Glass

text: Philip Glass (born January 31, 1937) is an American composer and pianist. He is widely regarded as one of the most influential composers of the late 20th century. Glass's work has been associated with minimalism, being built up from repetitive phrases and shifting layers. Glass describes himself as a composer of "music with repetitive structures", which he has helped evolve stylistically.


title: Philip Glass

text: Glass founded the Philip Glass Ensemble, with which he still performs on keyboards. He has written fifteen operas, numerous chamber operas and musical theatre works, fourteen symphonies, twelve concertos, nine string quartets and various other chamber music, and several film scores. Three of his film scores have been nominated for an Academy Award.


title: Philip Glass

text: Philip Glass was born in Baltimore, Maryland, on January 31, 1937, the son of Ida (née Gouline) and Benjamin Charles Glass. His family were Lithuanian-Jewish emigrants. His father owned a record store and his mother was a librarian. In his memoir, Glass recalls that at the end of World War II his mother aided Jewish Holocaust survivors, inviting recent arrivals to America to stay at their home until they could find a job and a place to live. She developed a plan to help them learn English and develop skills so they could find work. His sister, Sheppie, would later do similar work as an active member of the International Rescue Committee.


title: Philip Glass

text: Glass developed his appreciation of music from his father, discovering later his father's side of the family had many musicians. His cousin Cevia was a classical pianist, while others had been in vaudeville. He learned his family was also related to Al Jolson.Glass's father often received promotional copies of new recordings at his music store. Glass spent many hours listening to them, developing his knowledge and taste in music. This openness to modern sounds affected Glass at an early age:


title: Philip Glass

text: The elder Glass promoted both new recordings and a wide selection of composers to his customers, sometimes convincing them to try something new by allowing them to return records they didn't like. His store soon developed a reputation as Baltimore's leading source of modern music. Glass built a sizable record collection from the unsold records in his father's store, including modern classical music such as Hindemith, Bartók, Schoenberg, Shostakovich and Western classical music including Beethoven's string quartets and Schubert's B Piano Trio. Glass cites Schubert's work as a "big influence" growing up. In a 2011 interview, Glass stated that Franz Schubert—with whom he shares a birthday—is his favorite composer.


title: Philip Glass

text: He studied the flute as a child at the Peabody Preparatory of the Peabody Institute of Music. At the age of 15, he entered an accelerated college program at the University of Chicago where he studied mathematics and philosophy. In Chicago, he discovered the serialism of Anton Webern and composed a twelve-tone string trio. In 1954, Glass traveled to Paris, where he encountered the films of Jean Cocteau, which made a lasting impression on him. He visited artists' studios and saw their work; Glass recalls, "the bohemian life you see in [Cocteau's] "Orphée" was the life I ... was attracted to, and those were the people I hung out with."


title: Philip Glass

text: Glass studied at the Juilliard School of Music where the keyboard was his main instrument. His composition teachers included Vincent Persichetti and William Bergsma. Fellow students included Steve Reich and Peter Schickele. In 1959, he was a winner in the BMI Foundation's BMI Student Composer Awards, an international prize for young composers. In the summer of 1960, he studied with Darius Milhaud at the summer school of the Aspen Music Festival and composed a violin concerto for a fellow student, Dorothy Pixley-Rothschild. After leaving Juilliard in 1962, Glass moved to Pittsburgh and worked as a school-based composer-in-residence in the public school system, composing various choral, chamber, and orchestral music.


title: Philip Glass

text: In 1964, Glass received a Fulbright Scholarship; his studies in Paris with the eminent composition teacher Nadia Boulanger, from autumn of 1964 to summer of 1966, influenced his work throughout his life, as the composer admitted in 1979: "The composers I studied with Boulanger are the people I still think about most—Bach and Mozart."


title: Philip Glass

text: Glass later stated in his autobiography "Music by Philip Glass" (1987) that the new music performed at Pierre Boulez's "Domaine Musical" concerts in Paris lacked any excitement for him (with the notable exceptions of music by John Cage and Morton Feldman), but he was deeply impressed by new films and theatre performances. His move away from modernist composers such as Boulez and Stockhausen was nuanced, rather than outright rejection: "That generation wanted disciples and as we didn't join up it was taken to mean that we hated the music, which wasn't true. We'd studied them at Juilliard and knew their music. How on earth can you reject Berio? Those early works of Stockhausen are still beautiful. But there was just no point in attempting to do their music better than they did and so we started somewhere else."


title: Philip Glass

text: During this time, he encountered revolutionary films of the French New Wave, such as those of Jean-Luc Godard and François Truffaut, which upended the rules set by an older generation of artists, and Glass made friends with American visual artists (the sculptor Richard Serra and his wife Nancy Graves), actors and directors (JoAnne Akalaitis, Ruth Maleczech, David Warrilow, and Lee Breuer, with whom Glass later founded the experimental theatre group Mabou Mines). Together with Akalaitis (they married in 1965), Glass in turn attended performances by theatre groups including Jean-Louis Barrault's Odéon theatre, The Living Theatre and the Berliner Ensemble in 1964 to 1965. These significant encounters resulted in a collaboration with Breuer for which Glass contributed music for a 1965 staging of Samuel Beckett's "Comédie" ("Play", 1963). The resulting piece (written for two soprano saxophones) was directly influenced by the play's open-ended, repetitive and almost musical structure and was the first one of a series of four early pieces in a minimalist, yet still dissonant, idiom. After "Play", Glass also acted in 1966 as music director of a Breuer production of Brecht's "Mother Courage and Her Children", featuring the theatre score by Paul Dessau.


title: Philip Glass

text: In parallel with his early excursions in experimental theatre, Glass worked in winter 1965 and spring 1966 as a music director and composer on a film score ("Chappaqua", Conrad Rooks, 1966) with Ravi Shankar and Alla Rakha, which added another important influence on Glass's musical thinking. His distinctive style arose from his work with Shankar and Rakha and their perception of rhythm in Indian music as being entirely additive. He renounced all his compositions in a moderately modern style resembling Milhaud's, Aaron Copland's, and Samuel Barber's, and began writing pieces based on repetitive structures of Indian music and a sense of time influenced by Samuel Beckett: a piece for two actresses and chamber ensemble, a work for chamber ensemble and his first numbered string quartet (No. 1, 1966).


title: Philip Glass

text: Glass then left Paris for northern India in 1966, where he came in contact with Tibetan refugees and began to gravitate towards Buddhism. He met Tenzin Gyatso, the 14th Dalai Lama, in 1972, and has been a strong supporter of the Tibetan independence ever since.


title: Philip Glass

text: Shortly after arriving in New York City in March 1967, Glass attended a performance of works by Steve Reich (including the ground-breaking minimalist piece "Piano Phase"), which left a deep impression on him; he simplified his style and turned to a radical "consonant vocabulary". Finding little sympathy from traditional performers and performance spaces, Glass eventually formed an ensemble with fellow ex-student Jon Gibson, and others, and began performing mainly in art galleries and studio lofts of SoHo. The visual artist Richard Serra provided Glass with Gallery contacts, while both collaborated on various sculptures, films and installations; from 1971 to 1974, he was Serra's regular studio assistant.


title: Philip Glass

text: Between summer of 1967 and the end of 1968, Glass composed nine works, including "Strung Out" (for amplified solo violin, composed in summer of 1967), "Gradus" (for solo saxophone, 1968), "Music in the Shape of a Square" (for two flutes, composed in May 1968, an homage to Erik Satie), "How Now" (for solo piano, 1968) and "1+1" (for amplified tabletop, November 1968) which were "clearly designed to experiment more fully with his new-found minimalist approach". The first concert of Glass's new music was at Jonas Mekas's Film-Makers Cinemathèque (Anthology Film Archives) in September 1968. This concert included the first work of this series with "Strung Out" (performed by the violinist Pixley-Rothschild) and "Music in the Shape of a Square" (performed by Glass and Gibson). The musical scores were tacked on the wall, and the performers had to move while playing. Glass's new works met with a very enthusiastic response by the audience which consisted mainly of visual and performance artists who were highly sympathetic to Glass's reductive approach.


title: Philip Glass

text: Apart from his music career, Glass had a moving company with his cousin, the sculptor Jene Highstein, and also worked as a plumber and cab driver (during 1973 to 1978). He recounts installing a dishwasher and looking up from his work to see an astonished Robert Hughes, "Time" magazine's art critic, staring at him. During this time, he made friends with other New York-based artists such as Sol LeWitt, Nancy Graves, Michael Snow, Bruce Nauman, Laurie Anderson, and Chuck Close (who created a now-famous portrait of Glass). (Glass returned the compliment in 2005 with "A Musical Portrait of Chuck Close" for piano.)


title: Philip Glass

text: With "1+1" and "Two Pages" (composed in February 1969), Glass turned to a more "rigorous approach" to his "most basic minimalist technique, additive process", pieces which were followed in the same year by "Music in Contrary Motion" and "Music in Fifths" (a kind of homage to his composition teacher Nadia Boulanger, who pointed out "hidden fifths" in his works but regarded them as cardinal sins). Eventually Glass's music grew less austere, becoming more complex and dramatic, with pieces such as "Music in Similar Motion" (1969), and "Music with Changing Parts" (1970). These pieces were performed by the Philip Glass Ensemble in the Whitney Museum of American Art in 1969 and in the Solomon R. Guggenheim Museum in 1970, often encountering hostile reaction from critics, but Glass's music was also met with enthusiasm from younger artists such as Brian Eno and David Bowie (at the Royal College of Art ca. 1970). Eno described this encounter with Glass's music as one of the "most extraordinary musical experiences of [his] life", as a "viscous bath of pure, thick energy", concluding "this was actually the most detailed music I'd ever heard. It was all intricacy, exotic harmonics". In 1970, Glass returned to the theatre, composing music for the theatre group Mabou Mines, resulting in his first minimalist pieces employing voices: "Red Horse Animation" and "Music for Voices" (both 1970, and premiered at the Paula Cooper Gallery).


title: Philip Glass

text: After differences of opinion with Steve Reich in 1971, Glass formed the Philip Glass Ensemble (while Reich formed Steve Reich and Musicians), an amplified ensemble including keyboards, wind instruments (saxophones, flutes), and soprano voices.


title: Philip Glass

text: Glass's music for his ensemble culminated in the four-hour-long "Music in Twelve Parts" (1971–1974), which began as a single piece with twelve instrumental parts but developed into a cycle that summed up Glass's musical achievement since 1967, and even transcended it—the last part features a twelve-tone theme, sung by the soprano voice of the ensemble. "I had broken the rules of modernism and so I thought it was time to break some of my own rules", according to Glass. Though he finds the term minimalist inaccurate to describe his later work, Glass does accept this term for pieces up to and including "Music in 12 Parts", excepting this last part which "was the end of minimalism" for Glass. As he pointed out: "I had worked for eight or nine years inventing a system, and now I'd written through it and come out the other end." He now prefers to describe himself as a composer of "music with repetitive structures".


title: Philip Glass

text: Glass continued his work with a series of instrumental works, called "Another Look at Harmony" (1975–1977). For Glass, this series demonstrated a new start, hence the title: "What I was looking for was a way of combining harmonic progression with the rhythmic structure I had been developing, to produce a new overall structure. ... I'd taken everything out with my early works and it was now time to decide just what I wanted to put in—a process that would occupy me for several years to come."


title: Philip Glass

text: Parts 1 and 2 of "Another Look at Harmony" were included in a collaboration with Robert Wilson, a piece of musical theater later designated by Glass as the first opera of his portrait opera trilogy: "Einstein on the Beach". Composed in spring to fall of 1975 in close collaboration with Wilson, Glass's first opera was first premiered in summer 1976 at the Festival d'Avignon, and in November of the same year to a mixed and partly enthusiastic reaction from the audience at the Metropolitan Opera in New York City. Scored for the Philip Glass Ensemble, solo violin, chorus, and featuring actors (reciting texts by Christopher Knowles, Lucinda Childs and Samuel M. Johnson), Glass's and Wilson's essentially plotless opera was conceived as a "metaphorical look at Albert Einstein: scientist, humanist, amateur musician—and the man whose theories ... led to the splitting of the atom", evoking nuclear holocaust in the climactic scene, as critic Tim Page pointed out. As with "Another Look at Harmony", ""Einstein" added a new functional harmony that set it apart from the early conceptual works". Composer Tom Johnson came to the same conclusion, comparing the solo violin music to Johann Sebastian Bach, and the "organ figures ... to those Alberti basses Mozart loved so much". The piece was praised by "The Washington Post" as "one of the seminal artworks of the century".


title: Philip Glass

text: "Einstein on the Beach" was followed by further music for projects by the theatre group Mabou Mines such as "Dressed like an Egg" (1975), and again music for plays and adaptations from prose by Samuel Beckett, such as "The Lost Ones" (1975), "Cascando" (1975), "Mercier and Camier" (1979). Glass also turned to other media; two multi-movement instrumental works for the Philip Glass Ensemble originated as music for film and TV: "North Star" (1977 score for the documentary "" by François de Menil and Barbara Rose) and four short cues for the children's TV series "Sesame Street" named "Geometry of Circles" (1979).


title: Philip Glass

text: Another series, "Fourth Series" (1977–79), included music for chorus and organ ("Part One", 1977), organ and piano ("Part Two" and "Part Four", 1979), and music for a radio adaption of Constance DeJong's novel "Modern Love" ("Part Three", 1978). "Part Two" and "Part Four" were used (and hence renamed) in two dance productions by choreographer Lucinda Childs (who had already contributed to and performed in "Einstein on the Beach"). "Part Two" was included in "Dance" (a collaboration with visual artist Sol LeWitt, 1979), and "Part Four" was renamed as "Mad Rush", and performed by Glass on several occasions such as the first public appearance of the 14th Dalai Lama in New York City in fall 1981. The piece demonstrates Glass's turn to more traditional models: the composer added a conclusion to an open-structured piece which "can be interpreted as a sign that he [had] abandoned the radical non-narrative, undramatic approaches of his early period", as the pianist Steffen Schleiermacher points out.


title: Philip Glass

text: In spring 1978, Glass received a commission from the Netherlands Opera (as well as a Rockefeller Foundation grant) which "marked the end of his need to earn money from non-musical employment". With the commission Glass continued his work in music theater, composing his opera "Satyagraha" (composed in 1978–1979, premiered in 1980 at Rotterdam), based on the early life of Mahatma Gandhi in South Africa, Leo Tolstoy, Rabindranath Tagore, and Martin Luther King Jr. For "Satyagraha", Glass worked in close collaboration with two "SoHo friends": the writer Constance deJong, who provided the libretto, and the set designer Robert Israel. This piece was in other ways a turning point for Glass, as it was his first work since 1963 scored for symphony orchestra, even if the most prominent parts were still reserved for solo voices and chorus. Shortly after completing the score in August 1979, Glass met the conductor Dennis Russell Davies, whom he helped prepare for performances in Germany (using a piano-four-hands version of the score); together they started to plan another opera, to be premiered at the Stuttgart State Opera.


title: Philip Glass

text: While planning a third part of his "Portrait Trilogy", Glass turned to smaller music theatre projects such as the non-narrative "Madrigal Opera" (for six voices and violin and viola, 1980), and "The Photographer", a biographic study on the photographer Eadweard Muybridge (1982). Glass also continued to write for the orchestra with the score of "Koyaanisqatsi" (Godfrey Reggio, 1981–1982). Some pieces which were not used in the film (such as "Façades") eventually appeared on the album "Glassworks" (1982, CBS Records), which brought Glass's music to a wider public.


title: Philip Glass

text: The "Portrait Trilogy" was completed with "Akhnaten" (1982–1983, premiered in 1984), a vocal and orchestral composition sung in Akkadian, Biblical Hebrew, and Ancient Egyptian. In addition, this opera featured an actor reciting ancient Egyptian texts in the language of the audience. "Akhnaten" was commissioned by the Stuttgart Opera in a production designed by Achim Freyer. It premiered simultaneously at the Houston Opera in a production directed by David Freeman and designed by Peter Sellars. At the time of the commission, the Stuttgart Opera House was undergoing renovation, necessitating the use of a nearby playhouse with a smaller orchestra pit. Upon learning this, Glass and conductor Dennis Russell Davies visited the playhouse, placing music stands around the pit to determine how many players the pit could accommodate. The two found they could not fit a full orchestra in the pit. Glass decided to eliminate the violins, which had the effect of "giving the orchestra a low, dark sound that came to characterize the piece and suited the subject very well". As Glass remarked in 1992, "Akhnaten" is significant in his work since it represents a "first extension out of a triadic harmonic language", an experiment with the polytonality of his teachers Persichetti and Milhaud, a musical technique which Glass compares to "an optical illusion, such as in the paintings of Josef Albers".


title: Philip Glass

text: Glass again collaborated with Robert Wilson on another opera, "" (1983, premiered in 1984), which also functioned as the final part (the Rome section) of Wilson's epic work by the same name, originally planned for an "international arts festival that would accompany the Olympic Games in Los Angeles". (Glass also composed a prestigious work for chorus and orchestra for the opening of the Games, "The Olympian: Lighting of the Torch and Closing "). The premiere of "The CIVIL warS" in Los Angeles never materialized and the opera was in the end premiered at the Opera of Rome. Glass's and Wilson's opera includes musical settings of Latin texts by the 1st-century-Roman playwright Seneca and allusions to the music of Giuseppe Verdi and from the American Civil War, featuring the 19th century figures Giuseppe Garibaldi and Robert E. Lee as characters.


title: Philip Glass

text: In the mid-1980s, Glass produced "works in different media at an extraordinarily rapid pace". Projects from that period include music for dance (Glass Pieces choreographed for New York City Ballet by Jerome Robbins in 1983 to a score drawn from existing Glass compositions created for other media including an excerpt from "Akhnaten"; and "In the Upper Room", Twyla Tharp, 1986), music for theatre productions "Endgame" (1984) and "Company" (1983). Beckett vehemently disapproved of the production of "Endgame" at the American Repertory Theater (Cambridge, Massachusetts), which featured JoAnne Akalaitis's direction and Glass's "Prelude" for timpani and double bass, but in the end, he authorized the music for "Company", four short, intimate pieces for string quartet that were played in the intervals of the dramatization. This composition was initially regarded by the composer as a piece of Gebrauchsmusik ('music for use')—"like salt and pepper ... just something for the table", as he noted. Eventually "Company" was published as Glass's String Quartet No. 2 and in a version for string orchestra, being performed by ensembles ranging from student orchestras to renowned formations such as the Kronos Quartet and the Kremerata Baltica.


title: Philip Glass

text: This interest in writing for the string quartet and the string orchestra led to a chamber and orchestral film score for "" (Paul Schrader, 1984–85), which Glass recently described as his "musical turning point" that developed his "technique of film scoring in a very special way".


title: Philip Glass

text: Glass also dedicated himself to vocal works with two sets of songs, "Three Songs for chorus" (1984, settings of poems by Leonard Cohen, Octavio Paz and Raymond Lévesque), and a song cycle initiated by CBS Masterworks Records: "Songs from Liquid Days" (1985), with texts by songwriters such as David Byrne, Paul Simon, in which the Kronos Quartet is featured (as it is in "Mishima") in a prominent role. Glass also continued his series of operas with adaptations from literary texts such as "The Juniper Tree" (an opera collaboration with composer Robert Moran, 1984), Edgar Allan Poe's "The Fall of the House of Usher" (1987), and also worked with novelist Doris Lessing on the opera "The Making of the Representative for Planet 8" (1985–86, and performed by the Houston Grand Opera and English National Opera in 1988).


title: Philip Glass

text: Compositions such as "Company", "Facades" and String Quartet No. 3 (the last two extracted from the scores to "Koyaanisqatsi" and "Mishima") gave way to a series of works more accessible to ensembles such as the string quartet and symphony orchestra, in this returning to the structural roots of his student days. In taking this direction his chamber and orchestral works were also written in a more and more traditional and lyrical style. In these works, Glass often employs old musical forms such as the chaconne and the passacaglia—for instance in "Satyagraha", the Violin Concerto No. 1 (1987), Symphony No. 3 (1995), "Echorus" (1995) and also recent works such as Symphony No. 8 (2005), and "Songs and Poems for Solo Cello" (2006).


title: Philip Glass

text: A series of orchestral works originally composed for the concert hall commenced with the three-movement Violin Concerto No. 1 (1987). This work was commissioned by the American Composers Orchestra and written for and in close collaboration with the violinist Paul Zukofsky and the conductor Dennis Russel Davies, who since then has encouraged the composer to write numerous orchestral pieces. The Concerto is dedicated to the memory of Glass's father: "His favorite form was the violin concerto, and so I grew up listening to the Mendelssohn, the Paganini, the Brahms concertos. ... So when I decided to write a violin concerto, I wanted to write one that my father would have liked." Among its multiple recordings, in 1992, the Concerto was performed and recorded by Gidon Kremer and the Vienna Philharmonic. This turn to orchestral music was continued with a symphonic trilogy of "portraits of nature", commissioned by the Cleveland Orchestra, the Rotterdam Philharmonic Orchestra, and the Atlanta Symphony Orchestra: "The Light" (1987), "The Canyon" (1988), and "Itaipu" (1989).


title: Philip Glass

text: While composing for symphonic ensembles, Glass also composed music for piano, with the cycle of five movements titled "Metamorphosis" (adapted from music for a theatrical adaptation of Franz Kafka's "The Metamorphosis"), and for the Errol Morris film "The Thin Blue Line", 1988. In the same year Glass met the poet Allen Ginsberg by chance in a book store in the East Village of New York City, and they immediately "decided on the spot to do something together, reached for one of Allen's books and chose "Wichita Vortex Sutra"", a piece for reciter and piano which in turn developed into a music theatre piece for singers and ensemble, "Hydrogen Jukebox" (1990).


title: Philip Glass

text: Glass also returned to chamber music; he composed two String Quartets (No. 4 "Buczak" in 1989 and No. 5 in 1991), and chamber works which originated as incidental music for plays, such as "Music from "The Screens"" (1989/1990). This work originated in one of many theater music collaborations with the director JoAnne Akalaitis, who originally asked the Gambian musician Foday Musa Suso "to do the score [for Jean Genet's "The Screens"] in collaboration with a western composer". Glass had already collaborated with Suso in the film score to "Powaqqatsi" (Godfrey Reggio, 1988). "Music from "The Screens"" is on occasion a touring piece for Glass and Suso (one set of tours also included percussionist Yousif Sheronick ), and individual pieces found their way into the repertoire of Glass and the cellist Wendy Sutter. Another collaboration was a collaborative recording project with Ravi Shankar, initiated by Peter Baumann (a member of the band Tangerine Dream), which resulted in the album "Passages" (1990).


title: Philip Glass

text: In the late 1980s and early 1990s, Glass's projects also included two highly prestigious opera commissions based on the life of explorers: "The Voyage" (1992), with a libretto by David Henry Hwang, was commissioned by the Metropolitan Opera for the 500th anniversary of the discovery of America by Christopher Columbus; and "White Raven" (1991), about Vasco da Gama, a collaboration with Robert Wilson and composed for the closure of the 1998 World Fair in Lisbon. Especially in "The Voyage", the composer "explore[d] new territory", with its "newly arching lyricism", "Sibelian starkness and sweep", and "dark, brooding tone ... a reflection of its increasingly chromatic (and dissonant) palette", as one commentator put it.


title: Philip Glass

text: After these operas, Glass began working on a symphonic cycle, commissioned by the conductor Dennis Russell Davies, who told Glass at the time: "I'm not going to let you ... be one of those opera composers who never write a symphony". Glass responded with a pair of three-movement symphonies (""Low"" [1992], and Symphony No. 2 [1994]); his first in an ongoing series of symphonies is a combination of the composer's own musical material with themes featured in prominent tracks of the David Bowie/Brian Eno album "Low" (1977), whereas Symphony No. 2 is described by Glass as a study in polytonality. He referred to the music of Honegger, Milhaud, and Villa-Lobos as possible models for his symphony. With the Concerto Grosso (1992), Symphony No. 3 (1995), a Concerto for Saxophone Quartet and Orchestra (1995), written for the Rascher Quartet (all commissioned by conductor Dennis Russel Davies), and "Echorus" (1994/95), a more transparent, refined, and intimate chamber-orchestral style paralleled the excursions of his large-scale symphonic pieces. In the four movements of his Third Symphony, Glass treats a 19-piece string orchestra as an extended chamber ensemble. In the third movement, Glass re-uses the chaconne as a formal device; one commentator characterized Glass's symphony as one of the composer's "most tautly unified works". The third Symphony was closely followed by a fourth, subtitled "Heroes" (1996), commissioned the American Composers Orchestra. Its six movements are symphonic reworkings of themes by Glass, David Bowie, and Brian Eno (from their album ""Heroes"", 1977); as in other works by the composer, it is also a hybrid work and exists in two versions: one for the concert hall, and another, shorter one for dance, choreographed by Twyla Tharp.


title: Philip Glass

text: Another commission by Dennis Russell Davies was a second series for piano, the "Etudes" for Piano (dedicated to Davies as well as the production designer Achim Freyer); the complete first set of ten Etudes has been recorded and performed by Glass himself. Bruce Brubaker and Dennis Russell Davies have each recorded the original set of six. Most of the Etudes are composed in the post-minimalist and increasingly lyrical style of the times: "Within the framework of a concise form, Glass explores possible sonorities ranging from typically Baroque passagework to Romantically tinged moods". Some of the pieces also appeared in different versions such as in the theatre music to Robert Wilson's "Persephone" (1994, commissioned by the Relache Ensemble) or "Echorus" (a version of Etude No. 2 for two violins and string orchestra, written for Edna Mitchell and Yehudi Menuhin 1995).


title: Philip Glass

text: Glass's prolific output in the 1990s continued to include operas with an opera triptych (1991–1996), which the composer described as an "homage" to writer and film director Jean Cocteau, based on his prose and cinematic work: "Orphée" (1950), "La Belle et la Bête" (1946), and the novel "Les Enfants terribles" (1929, later made into a film by Cocteau and Jean-Pierre Melville, 1950). In the same way the triptych is also a musical homage to the work of the group of French composers associated with Cocteau, Les Six (and especially to Glass's teacher Darius Milhaud), as well as to various 18th-century composers such as Gluck and Bach whose music featured as an essential part of the films by Cocteau.


title: Philip Glass

text: The inspiration of the first part of the trilogy, "Orphée" (composed in 1991, and premiered in 1993 at the American Repertory Theatre) can be conceptually and musically traced to Gluck's opera "Orfeo ed Euridice" ("Orphée et Euridyce", 1762/1774), which had a prominent part in Cocteau's 1949 film "Orphee". One theme of the opera, the death of Eurydice, has some similarity to the composer's personal life: the opera was composed after the unexpected death in 1991 of Glass's wife, artist Candy Jernigan: "... One can only suspect that Orpheus' grief must have resembled the composer's own", K. Robert Schwartz suggests. The opera's "transparency of texture, a subtlety of instrumental color, ... a newly expressive and unfettered vocal writing" was praised, and "The Guardian's" critic remarked "Glass has a real affinity for the French text and sets the words eloquently, underpinning them with delicately patterned instrumental textures".


title: Philip Glass

text: For the second opera, "La Belle et la Bête" (1994, scored for either the Philip Glass Ensemble or a more conventional chamber orchestra), Glass replaced the soundtrack (including Georges Auric's film music) of Cocteau's film, wrote "a new fully operatic score and synchronize[d] it with the film". The final part of the triptych returned again to a more traditional setting with the "Dance Opera" "Les Enfants terribles" (1996), scored for voices, three pianos and dancers, with choreography by Susan Marshall. The characters are depicted by both singers and dancers. The scoring of the opera evokes Bach's Concerto for Four Harpsichords, but in another way also "the snow, which falls relentlessly throughout the opera ... bearing witness to the unfolding events. Here time stands still. There is only music, and the movement of children through space" (Glass).


title: Philip Glass

text: In the late 1990s and early 2000s, Glass's lyrical and romantic styles peaked with a variety of projects: operas, theatre and film scores (Martin Scorsese's "Kundun", 1997, Godfrey Reggio's "Naqoyqatsi", 2002, and Stephen Daldry's "The Hours", 2002), a series of five concerts, and three symphonies centered on orchestra-singer and orchestra-chorus interplay. Two symphonies, Symphony No. 5 "Choral" (1999) and Symphony No. 7 "Toltec" (2004), and the song cycle "Songs of Milarepa" (1997) have a meditative theme. The operatic Symphony No. 6 "Plutonian Ode" (2002) for soprano and orchestra was commissioned by the Brucknerhaus, Linz, and Carnegie Hall in celebration of Glass's sixty-fifth birthday, and developed from Glass's collaboration with Allen Ginsberg (poet, piano—Ginsberg, Glass), based on his poem of the same name.


title: Philip Glass

text: Besides writing for the concert hall, Glass continued his ongoing operatic series with adaptions from literary texts: "The Marriages of Zones 3, 4 and 5" ([1997] story-libretto by Doris Lessing), "In the Penal Colony" (2000, after the story by Franz Kafka), and the chamber opera "The Sound of a Voice" (2003, with David Henry Hwang), which features the Pipa, performed by Wu Man at its premiere. Glass also collaborated again with the co-author of "Einstein on the Beach", Robert Wilson, on "Monsters of Grace" (1998), and created a biographic opera on the life of astronomer Galileo Galilei (2001).