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CARNET

CARNET (Croatian Academic and Research Network, Hrvatska akademska i istraživačka mreža) is the national research and education network of Croatia. It is funded from the government budget and it operates from offices in Zagreb and five other cities.

CARNET was established in 1991 as a project of the Ministry of Science and Technology of the Republic of Croatia. In March 1995 the Government of the Republic of Croatia passed the Decree on founding of the CARNET institution with the purpose of facilitating progress of individuals, as well as of the society as a whole, through the use of new information technologies.

CARNET's activities can be divided in three basic areas: Internet service provision, encouragement of information society development and education for the new era.

The institution
A body responsible for coordinating the establishment of the Croatian educational computer network has been established on 3 October 1991. That was the beginning of the work of the Croatian Academic and Research Network - CARNET, the first Internet Service Provider (ISP) in Croatia. In the several years that followed CARNET was the only Internet service provider in Croatia, providing the service free of charge, not only to the academic community, but to all citizens of the Republic of Croatia as well.

In November 1992 the first international communication connection was established, which connected CARNET Internet exchange point in Zagreb to Austria. By that act Croatia became a part of the world computer network – the Internet.

During 1992, the first equipment was procured and the backbone of the CARNET network was built. Institutions in Croatia were connected at the speed of 19 - 200 kbit/s, while the whole network was connected to the Internet through Austria at the speed of 64 kbit/s. The first institutions to be connected to the Internet were the University Computing Centre - SRCE, the Faculty of Electrical Engineering and Computing in Zagreb, the Ruđer Bošković Institute, the Faculty of Science, the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split, the Faculty of Engineering in Rijeka, the Faculty of Economics in Osijek and the Ministry of Science and Technology.

During the first months of 1993, CARNET was assigned the administration over the top-level .hr domain by the international organisation called the Internet Assigned Numbers Authority (IANA). In October 1994, CARNET started offering the first Internet courses to its users and, in time, user education became one of CARNET’s most important activities.

Network
In 1996, the backbone of CARNET network was upgraded by introducing the ATM technology which enables real-time transfer of image and sound at the basic speed of 155 Mbit/s.

In January 1997, the first distance lecture in Croatia was organized through the CARNET ATM core between the Rectorate of the Osijek University and the Faculty of Electrical Engineering and Computing in Zagreb. GÉANT, the pan-European academic and research network, was put into service on 1 December 2001, and CARNET, among others, connected to it.

In cooperation with the University Computing Centre - SRCE, in 2003 CARNET released the Giga CARNET project in order to use gigabit technologies to develop a high quality infrastructure for CARNET member institutions, faculties and research institutes. In the framework of the Giga CARNET project, in February 2004 CARNET was enabled, through the connection to the GÉANT network, to have a twice-faster connection to similar academic and research networks in Europe and all over the world (at the speed of 1.2 Gbit/s instead of the former 622 Mbit/s).

As a necessary requirement for further cooperation between CARNET and the world's academic and research communities, in June 2007 the speed of CARNET's connection towards the GÉANT network was increased to 10 Gbit/s.

Chronology

2020 Cyberattack
On 16 March, Minister of Education Blaženka Divjak confirmed that the same day CARNET, responsible for online classes in Croatia, was a victim of a cyberattack making the online classes impossible at that moment.

Organisation
CARNET operates through services and projects integrated in eight departments:
 * Network Infrastructure Department
 * Computer and IT Systems and Services Department
 * Computer Security Department
 * National CERT Department
 * User Support Department
 * Education Support Department
 * General and Financial Activities Department
 * Office of the CEO

The CEO coordinates the activities at the level of the entire institution and outside it, acts on behalf of the institution and represents CARNET in public. CARNET Executive Committee consists of the CEO, the vice CEO and deputy CEOs (heads of the said departments). The Committee coordinates short- and long-term planning, makes decisions on business organisation and is responsible for the relations with the government bodies, users, partners and the public.

CARNET is run by the Managing Council which represents the interests of CARNET founders, the Government of the Republic of Croatia. Managing Council members are appointed by the Minister of Science, Education and Sports.

The Users Board is CARNET's advisory body consisting of all CARNET coordinators at CARNET member institutions as the representatives of the academic community, heads of county-level computer science councils as the representatives of school system users, and the CARNET CEO.

Infrastructure
Basic activities of the Croatian Academic and Research Network - CARNET are network development, building and maintenance. CARNET network is a private network of the Croatian academic, scientific and research community and the primary and secondary school system institutions.

Network infrastructure is owned by the CARNET institution, but cables are rented from a number of telecommunication providers. CARNET network is an example of a WAN network which enables CARNET members throughout Croatia to be connected into a compact information and communication system.

CARNET network is a data network whose principal purpose is to transfer data through the TCP/IP protocol. The currently supported version of the TCP/IP protocol in the CARNET network as its integral part is version 4 (IPv4). The key characteristic of every private network is its connection to the global network - the Internet. The CARNET network established this connection through the GÉANT pan-European research network, with the current connection speed of 10 Gbit/s. The connection to other Internet service providers in Croatia has been implemented through the Croatian Internet Exchange Point – CIX.

In Croatia, the CARNET network connects the major Croatian towns and cities on the mainland and a number of settlements on the islands. The larger university centres (Dubrovnik, Osijek, Pula, Rijeka, Split, Zadar, Zagreb) have high speed connections (ranging from 155 Mbit/s to 1 Gbit/s), while smaller centres are connected at the speeds ranging from 2 Mbit/s to 100 Mbit/s. Zagreb has a particularly advanced infrastructure, connecting larger faculties and scientific institutions at the speeds of up to 10 Gbit/s. Thanks to the project "e-Split", which CARNET has accomplished in cooperation with the City of Split, Split is the first city in which CARNET has its own optical network. Through that optical network 158 CARNET member institutions, in the city area, are connected to CARNET network.

More than 900 institutions from the primary and secondary school systems are also connected to the CARNET network via ADSL connections, and schools on Croatian islands have been connected to CARNET network in the framework of the e-Islands project.

International cooperation
As part of its vision of inclusion of the Republic of Croatia in modern information society, CARNET participates in a series of international activities.

Parallel with the increase of physical link speed on GEANT network, there is an increased development of CARNET's parallel (human) link towards European and international academic Internet community. CARNET activities in the sphere of international cooperation are forming a stable communication channel towards foreign countries, providing CARNET with an opportunity to present Croatia and its academic research community.

International cooperation includes following the activities of other academic networks in Europe and participating in the work of international organisations that gather national, educational, academic and research networks. CARNET also promotes the inclusion of the Croatian academic community into international projects in the field of information technologies research and application and coordinates the participation of CARNET employees in international projects.

CARNET is active member of several international organisations:

 * Trans - European Research and Education Networking Association
 * The Internet Corporation for Assigned Names and Numbers
 * Réseaux IP Européens
 * Council of European National Top-Level Domain Registries
 * Forum of Incident Response and Security Teams (FIRST)
 * NREN Consortium

Users
CARNET users are member institutions and individual users.

CARNET member institutions are institutions belonging to the science and higher education system, as well as those belonging to the primary and secondary school systems. By obtaining the member status, institutions are connected to the CARNET network and entitled to use the CARNET services. CARNET has 241 member institutions from the academic community connected to the CARNET network at 418 locations. There are 1385 members from the primary and secondary school systems, connected at 1283 locations.

Individual users are higher education students and professors, scientists and persons employed in the academic and higher education community, primary and secondary school students, teachers and employees at primary and secondary schools and student homes.

At their respective central institution individual users obtain electronic identities in the AAI@EduHr system. Electronic identity is a virtual identity on the CARNET network which serves for user authentication and authorisation for different CARNET services and is necessary for the use of CARNET services.

Services

 * Internet Access: Continuous Connection, Net in School, E-islands, Mobile CARNET, Super/2D/3D CARNET, MetroCARNET, DUO.CARNET, OptiCARNET, Vipme CARNET, Stick2CARNET, Tele2CARNET, Homebox CARNET and CARNET Modem Entries.
 * Education: Online Courses, E-learning Academy, E-courses for Schools, Moodle, Teacher Training, National Distance Learning Portal "Nikola Tesla", Školska Učilica, Schools Portal, E-library, CARNET Users Conference CUC, Online Encyclopedia, Cisco Academy, Courses for CARNET System Engineers and Portal for System Engineers
 * Internet Services: Hosting Service for Primary and Secondary Schools, CMS for Schools, Electronic Identity, Public Server, CARNET Debian, Virtual Servers, VOOPIX, www.hr, SmartX, E-mail, Webmail, Web Space, Domains, NTP, News and FTP.
 * Multimedia: Room Videoconferences, Internet Transmission (streaming), Media on Demand and Adobe Connect Pro.
 * Computer Security: Abuse Service, Content Filtering, Security Advice Vulnerability Test, Server Certificates, Security Advice and Mediation in Resolving Computer Incidents.
 * Help and Support: User support service - helpdesk, Membership in the CARNET Network, Helpdesk for CARNET System Engineers and Membership in the CARNET Network.

title: CARNET


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Computer science and engineering

Computer science and engineering (CSE) is an academic program at many universities which comprises approaches of computer science and computer engineering. There is no clear division in computing between science and engineering, just like in the field of materials science and engineering. However, some classes are historically more related to computer science (e.g. data structures and algorithms), and other to computer engineering (e.g. computer architecture). CSE is also a term often used in Europe to translate the name of technical or engineering informatics academic programs. It is offered in both undergraduate as well postgraduate with specializations.

Academic courses
Academic programs vary between colleges, but typically include a combination of topics in computer science, computer engineering, and electrical engineering. Undergraduate courses usually include programming, algorithms and data structures, computer architecture, operating systems, computer networks, parallel computing, embedded systems, algorithms design, circuit analysis and electronics, digital logic and processor design, computer graphics, scientific computing, software engineering, database systems, digital signal processing, virtualization, computer simulations and games programming. CSE programs also include core subjects of theoretical computer science such as theory of computation, numerical methods, machine learning, programming theory and paradigms. Modern academic programs also cover emerging computing fields like image processing, data science, robotics, bio-inspired computing, computational biology, autonomic computing and artificial intelligence. Most CSE programs require introductory mathematical knowledge, hence the first year of study is dominated by mathematical courses, primarily discrete mathematics, mathematical analysis, linear algebra, probability, and statistics, as well as the introduction to physics and electrical and electronic engineering. Students usually also have the opportunity to choose one social science subject.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Computer science and engineering


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Philae (spacecraft)

Philae ( or ) was a robotic European Space Agency lander that accompanied the Rosetta spacecraft  until it separated to land on comet 67P/Churyumov–Gerasimenko, ten years and eight months after departing Earth. On 12 November 2014, Philae touched down on the comet, but it bounced when its anchoring harpoons failed to deploy and a thruster designed to hold the probe to the surface did not fire. After bouncing off the surface twice, Philae achieved the first-ever "soft" (nondestructive) landing on a comet nucleus,  although the lander's final, uncontrolled touchdown left it in a non-optimal location and orientation.

Despite the landing problems, the probe's instruments obtained the first images from a comet's surface. Several of the instruments on Philae made the first in-situ analysis of a comet nucleus, sending back data regarding the composition of the surface and outgassing from the subsurface. In October 2020, scientific journal Nature published an article revealing what Philae had discovered while it was operational on the surface of 67P/Churyumov–Gerasimenko.

On 15 November 2014 Philae entered safe mode, or hibernation, after its batteries ran down due to reduced sunlight and an off-nominal spacecraft orientation at the crash site. Mission controllers hoped that additional sunlight on the solar panels might be sufficient to reboot the lander. Philae communicated sporadically with Rosetta from 13 June to 9 July 2015,  but contact was then lost. The lander's location was known to within a few tens of metres but it could not be seen. Its location was finally identified in photographs taken by Rosetta on 2 September 2016 as the orbiter was sent on orbits closer to the comet. The now-silent Philae was lying on its side in a deep crack in the shadow of a cliff. Knowledge of its location would help in interpretation of the images it had sent. On 30 September 2016, the Rosetta spacecraft ended its mission by crashing in the comet's Ma'at region.

The lander is named after the Philae obelisk, which bears a bilingual inscription and was used along with the Rosetta Stone to decipher Egyptian hieroglyphs. Philae was monitored and operated from DLR's Lander Control Center in Cologne, Germany.

Mission
Philae mission was to land successfully on the surface of a comet, attach itself, and transmit data about the comet's composition. The Rosetta spacecraft and Philae lander were launched on an Ariane 5G+ rocket from French Guiana on 2 March 2004, 07:17 UTC, and travelled for 3,907 days (10.7 years) to Churyumov–Gerasimenko. Unlike the Deep Impact probe, which by design struck comet Tempel 1's nucleus on 4 July 2005, Philae is not an impactor. Some of the instruments on the lander were used for the first time as autonomous systems during the Mars flyby on 25 February 2007. CIVA, one of the camera systems, returned some images while the Rosetta instruments were powered down, while ROMAP took measurements of the Martian magnetosphere. Most of the other instruments needed contact with the surface for analysis and stayed offline during the flyby. An optimistic estimate of mission length following touchdown was "four to five months".

Scientific goals
The goals of the scientific mission have been summarised as follows: "'The scientific goals of its experiments focus on elemental, isotopic, molecular and mineralogical composition of the cometary material, the characterization of physical properties of the surface and subsurface material, the large-scale structure and the magnetic and plasma environment of the nucleus. In particular, surface and sub-surface samples will be acquired and sequentially analyzed by a suite of instruments. Measurements will be performed primarily during descent and along the first five days following touch-down. '"

Landing and surface operations
Philae remained attached to the Rosetta spacecraft after rendezvousing with Churyumov–Gerasimenko on 6 August 2014. On 15 September 2014, ESA announced "Site J" on the smaller lobe of the comet as the lander's destination. Following an ESA public contest in October 2014, Site J was renamed Agilkia in honour of Agilkia Island.

A series of four go/no-go checks were performed on 11–12 November 2014. One of the final tests before detachment from Rosetta showed that the lander's cold-gas thruster was not working correctly, but the "go" was given anyway, as it could not be repaired. Philae detached from Rosetta on 12 November 2014 at 08:35 UTC SCET.

Landing events

Philae landing signal was received by Earth communication stations at 16:03 UTC after a 28-minute delay. Unknown to mission scientists at that time, the lander had bounced. It began performing scientific measurements while slowly moving away from the comet and coming back down, confusing the science team. Further analysis showed that it bounced twice.

Philae first contact with the comet occurred at 15:34:04 UTC SCET. The probe rebounded off the comet's surface at 38 cm/s and rose to an altitude of approximately 1 km. For perspective, had the lander exceeded about 44 cm/s, it would have escaped the comet's gravity. After detecting the touchdown, Philae reaction wheel was automatically powered off, resulting in its momentum being transferred back into the lander. This caused the vehicle to begin rotating every 13 seconds. During this first bounce, at 16:20 UTC SCET, the lander is thought to have struck a surface prominence, which slowed its rotation to once every 24 seconds and sent the craft tumbling. Philae touched down a second time at 17:25:26 UTC SCET and rebounded at 3 cm/s. The lander came to a final stop on the surface at 17:31:17 UTC SCET. It sits in rough terrain, apparently in the shadow of a nearby cliff or crater wall, and is canted at an angle of around 30 degrees, but is otherwise undamaged. Its final location was determined initially by analysis of data from CONSERT in combination with the comet shape model based on images from the Rosetta orbiter, and later precisely by direct imaging from Rosetta.

An analysis of telemetry indicated that the initial impact was softer than expected, that the harpoons had not deployed, and that the thruster had not fired. The harpoon propulsion system contained 0.3 grams of nitrocellulose, which was shown by Copenhagen Suborbitals in 2013 to be unreliable in a vacuum.

Operations and communication loss

The primary battery was designed to power the instruments for about 60 hours. ESA expected that a secondary rechargeable battery would be partially filled by the solar panels attached to the outside of the lander, but the limited sunlight (90 minutes per 12.4-hour comet day ) at the actual landing site was inadequate to maintain Philae activities, at least in this phase of the comet's orbit.

On the morning of 14 November 2014, the battery charge was estimated to be only enough for continuing operations for the remainder of the day. After first obtaining data from instruments whose operation did not require mechanical movement, comprising about 80% of the planned initial science observations, both the MUPUS soil penetrator and the SD2 drill were commanded to deploy. Subsequently, MUPUS data as well as COSAC and Ptolemy data were returned. A final set of CONSERT data was also downlinked towards the end of operations. During the evening's transmission session, Philae was raised by 4 cm and its body rotated 35 degrees to more favourably position the largest solar panel to capture the most sunlight in the future. Shortly afterwards, electrical power dwindled rapidly and all instruments were forced to shut down. The downlink rate slowed to a trickle before coming to a stop. Contact was lost on 15 November at 00:36 UTC.

The German Aerospace Center's lander manager Stephan Ulamec stated: "Prior to falling silent, the lander was able to transmit all science data gathered during the First Science Sequence ... This machine performed magnificently under tough conditions, and we can be fully proud of the incredible scientific success Philae has delivered."

Instrument results
Data from the SESAME instrument determined that, rather than being "soft and fluffy" as expected, Philae first touchdown site held a large amount of water ice under a layer of granular material about 25 cm deep. It found that the mechanical strength of the ice was high and that cometary activity in that region was low. At the final landing site, the MUPUS instrument was unable to hammer very far into the comet's surface, despite power being gradually increased. This area was determined to have the consistency of solid ice or pumice.

In the atmosphere of the comet, the COSAC instrument detected the presence of molecules containing carbon and hydrogen. Soil elements could not be assessed, because the lander was unable to drill into the comet surface, likely due to hard ice. The SD2 drill went through the necessary steps to deliver a surface sample to the COSAC instrument, but nothing entered the COSAC ovens.

Upon Philae first touchdown on the comet's surface, COSAC measured material at the bottom of the vehicle, which was disturbed by the landing, while the Ptolemy instrument measured material at the top of the vehicle. Sixteen organic compounds were detected, four of which were seen for the first time on a comet, including acetamide, acetone, methyl isocyanate and propionaldehyde.

Reawakening and subsequent loss of communication
On 13 June 2015 at 20:28 UTC, ground controllers received an 85-second transmission from Philae, forwarded by Rosetta, indicating that the lander was in good health and had sufficiently recharged its batteries to come out of safe mode. Philae sent historical data indicating that although it had been operating earlier than 13 June 2015, it had been unable to contact Rosetta before that date. The lander reported that it was operating with 24 watts of electrical power at -35 C.

A new contact between Rosetta and Philae was confirmed on 19 June 2015. The first signal was received on the ground from Rosetta at 13:37 UTC, while a second signal was received at 13:54 UTC. These contacts lasted about two minutes each and delivered additional status data. By 26 June 2015, there had been a total of seven intermittent contacts between the lander and orbiter. There were two opportunities for contact between the two spacecraft each Earth day, but their duration and quality depended on the orientation of the transmitting antenna on Philae and the location of Rosetta along its trajectory around the comet. Similarly, as the comet rotated, Philae was not always in sunlight and thus not always generating enough power via its solar panels to receive and transmit signals. ESA controllers continued to try to establish a stable contact duration of at least 50 minutes.

Had Philae landed at the planned site of Agilkia in November 2014, its mission would probably have ended in March 2015 due to the higher temperatures of that location as solar heating increased. , Philae key remaining experiment was to drill into the comet's surface to determine its chemical composition. Ground controllers sent commands to power up the CONSERT radar instrument on 5 July 2015, but received no immediate response from the lander. Confirmation was eventually received on 9 July, when the lander transmitted measurement data from the instrument.

Immediately after its reawakening, housekeeping data suggested that the lander's systems were healthy, and mission control uploaded commands for Rosetta to establish a new orbit and nadir so as to optimize communications, diagnostics, and enable new science investigations with Philae. However, controllers had difficulties establishing a stable communications connection with the lander. The situation was not helped by the need to keep Rosetta at a greater and safer distance from the comet as it became more active. The last communication was on 9 July 2015, and mission controllers were unable to instruct Philae to carry out new investigations. Subsequently, Philae failed to respond to further commands, and by January 2016, controllers acknowledged no further communications were likely.

On 27 July 2016, at 09:00 UTC, ESA switched off the Electrical Support System Processor Unit (ESS) onboard Rosetta, making further communications with Philae impossible.

Location
The lander was located on 2 September 2016 by the narrow-angle camera aboard Rosetta as it was slowly making its descent to the comet. The search for the lander had been on-going during the Rosetta mission, using telemetry data and comparison of pictures taken before and after the lander's touchdown, looking for signs of the lander's specific reflectivity.

The search area was narrowed down to the most promising candidate, which was confirmed by a picture taken at a distance of 2.7 km, clearly showing the lander. The lander sits on its side wedged into a dark crevice of the comet, explaining the lack of electrical power and proper communication with the probe. Knowing its exact location provides information needed to put Philae two days of science into proper context.

Design
The lander was designed to deploy from the main spacecraft body and descend from an orbit of 22.5 km along a ballistic trajectory. It would touch down on the comet's surface at a velocity of around 1 m/s. The legs were designed to dampen the initial impact to avoid bouncing as the comet's escape velocity is only around 1 m/s, and the impact energy was intended to drive ice screws into the surface. Philae was to then fire a harpoon into the surface at 70 m/s to anchor itself. A thruster on top of Philae was to have fired to lessen the bounce upon impact and to reduce the recoil from harpoon firing. During the landing, the harpoons did not fire and the thruster failed to operate, leading to a multiple-contact landing.

Communications with Earth used the Rosetta orbiter as a relay station to reduce the electrical power needed. The mission duration on the surface was planned to be at least one week, but an extended mission lasting months was considered possible.

The main structure of the lander is made from carbon fiber, shaped into a plate maintaining mechanical stability, a platform for the science instruments, and a hexagonal "sandwich" to connect all the parts. The total mass is about 100 kg. Its exterior is covered with solar cells for power generation.

The Rosetta mission was originally planned to rendezvous with the comet 46P/Wirtanen. A failure in a previous Ariane 5 launch vehicle closed the launch window to reach the comet with the same rocket. It resulted in a change in target to the comet 67P/Churyumov–Gerasimenko. The larger mass of Churyumov–Gerasimenko and the resulting increased impact velocity required that the landing gear of the lander be strengthened.

Power management
Philae power management was planned for two phases. In the first phase, the lander operated solely on battery power. In the second phase, it was to run on backup batteries recharged by solar cells.

The power subsystem comprises two batteries: a non-rechargeable primary 1000 watt-hour battery to provide power for the first 60 hours and a secondary 140 watt-hour battery recharged by the solar panels to be used after the primary is exhausted. The solar panels cover 2.2 m2 and were designed to deliver up to 32 watts at a distance of 3 AU from the Sun.

Instruments

The science payload of the lander consists of ten instruments totalling 26.7 kg, making up just over one quarter of the mass of the lander.

 * APXS
 * The Alpha Particle X-ray Spectrometer detects alpha particles and X-rays, which provide information on the elemental composition of the comet's surface. The instrument is an improved version of the APXS on the Mars Pathfinder.

 * CIVA
 * The Comet Nucleus Infrared and Visible Analyser (sometimes given as ÇIVA ) is a group of seven identical cameras used to take panoramic pictures of the surface plus a visible-light microscope and an infrared spectrometer. The panoramic cameras (CIVA-P) are arranged on the sides of the lander at 60° intervals: five mono imagers and two others making up a stereo imager. Each camera has a 1024×1024 pixel CCD detector. The microscope and spectrometer (CIVA-M) are mounted on the base of the lander, and are used to analyse the composition, texture and albedo (reflectivity) of samples collected from the surface.

 * CONSERT
 * The COmet Nucleus Sounding Experiment by Radiowave Transmission used electromagnetic wave propagation to determine the comet's internal structure. A radar on Rosetta transmitted a signal through the nucleus to be received by a detector on Philae.

 * COSAC
 * The COmetary SAmpling and Composition instrument is a combined gas chromatograph and time-of-flight mass spectrometer to perform analysis of soil samples and determine the content of volatile components.

 * MUPUS
 * The MUlti-PUrpose Sensors for Surface and Sub-Surface Science instrument measured the density, thermal and mechanical properties of the comet's surface.

 * Ptolemy
 * An instrument measuring stable isotope ratios of key volatiles on the comet's nucleus. Parts of the instrument were manufactured by the Special Techniques Group at UKAEA.

 * ROLIS
 * The Rosetta Lander Imaging System is a CCD camera used to obtain high-resolution images during descent and stereo panoramic images of areas sampled by other instruments. The CCD detector consists of 1024×1024 pixels.

 * ROMAP
 * The Rosetta Lander Magnetometer and Plasma Monitor is a magnetometer and plasma sensor to study the nucleus' magnetic field and its interactions with the solar wind.

 * SD2
 * The Sampling, Drilling and Distribution system obtains soil samples from the comet and transfers them to the Ptolemy, COSAC, and CIVA instruments for in-situ analysis. SD2 contains four primary subsystems: drill, ovens, carousel, and volume checker. The drill system, made of steel and titanium, is capable of drilling to a depth of 230 mm, deploying a probe to collect samples, and delivering samples to the ovens. There are a total of 26 platinum ovens to heat samples—10 medium temperature ovens at 180 C and 16 high temperature ovens at 800 C—and one oven to clear the drill bit for reuse. The ovens are mounted on a rotating carousel that delivers the active oven to the appropriate instrument. The electromechanical volume checker determines how much material was deposited into an oven, and may be used to evenly distribute material on CIVA's optical windows. Development of SD2 was led by the Italian Space Agency with contributions by prime contractor Tecnospazio S.p.A. (now Selex ES S.p.A.) in charge of the system design and overall integration; the Italian company Tecnomare S.p.A., owned by Eni S.p.A., in charge of the design, development, and testing of the drilling/sampling tool and  the volume checker; Media Lario; and Dallara. The instrument's principal investigator is Amalia Ercoli-Finzi (Politecnico di Milano).

 * SESAME
 * The Surface Electric Sounding and Acoustic Monitoring Experiments used three instruments to measure properties of the comet's outer layers. The Cometary Acoustic Sounding Surface Experiment (CASSE) measures the way in which sound travels through the surface. The Permittivity Probe (PP) investigates its electrical characteristics, and the Dust Impact Monitor (DIM) measures dust falling back to the surface.

Analysis of comet
On 28 October 2020, it was reported that Philae had discovered, among other things, "low-strength primitive ice inside cometary boulders." This also included primitive water ice from the comet's estimated formation 4.5 billion years prior. This occurred primarily at the site of Philae's second touchdown onto the 67P/Churyumov–Gerasimenko, where the spacecraft successfully produced four distinct surface contacts on two adjoining cometary boulders. Philae was also able to drill 0.25 metres into the comet's boulder ice.

International contributions

 * Austria
 * The Austrian Space Research Institute developed the lander's anchor and two sensors within MUPUS, which are integrated into the anchor tips.

 * Belgium
 * The Belgian Institute for Space Aeronomy (BIRA) cooperated with different partners to build one of the sensors (DFMS) of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument. The Belgian Institute for Space Aeronomy (BIRA) and Royal Observatory of Belgium (ROB) provided information about the space weather conditions at Rosetta to support the landing of Philae. The main concern was solar proton events.

 * Canada
 * Two Canadian companies played a role in the mission. SED Systems, located on the University of Saskatchewan campus in Saskatoon, built three ground stations that were used to communicate with the Rosetta spacecraft. ADGA-RHEA Group of Ottawa provided MOIS (Manufacturing and Operating Information Systems) software which supported the procedures and command sequences operations software.

 * Finland
 * The Finnish Meteorological Institute provided the memory of the Command, Data and Management System (CDMS) and the Permittivity Probe (PP).

 * France
 * The French Space Agency, together with some scientific laboratories (IAS, SA, LPG, LISA) provided the system's overall engineering, radiocommunications, battery assembly, CONSERT, CIVA and the ground segment (overall engineering and development/operation of the Scientific Operation & Navigation Centre).

 * Germany
 * The German Space Agency (DLR) has provided the structure, thermal subsystem, flywheel, the Active Descent System (procured by DLR but made in Switzerland), ROLIS, downward-looking camera, SESAME, acoustic sounding and seismic instrument for Philae. It has also managed the project and did the level product assurance. The University of Münster built MUPUS (it was designed and built in Space Research Centre of Polish Academy of Sciences ) and the Braunschweig University of Technology the ROMAP instrument. The Max Planck Institute for Solar System Research made the payload engineering, eject mechanism, landing gear, anchoring harpoon, central computer, COSAC, APXS and other subsystems. The institute has led development and construction of COSAC and DIM, a part of SESAME, as well as contributed to the deveplopment and construction of ROMAP.

 * Hungary
 * The Command and Data Management Subsystem (CDMS) designed in the Wigner Research Centre for Physics of the Hungarian Academy of Sciences jointly with the Space and Ground Facilities Ltd. (a spin-off company of the Wigner Research Centre for Physics). The Power Subsystem (PSS) designed in the Department of Broadband Infocommunications and Electromagnetic Theory at Budapest University of Technology and Economics. CDMS is the fault tolerant central computer of the lander, while PSS assures that the power coming from the batteries and solar arrays are properly handled, controls battery charging and manages the onboard power distribution.

 * Ireland
 * Captec Ltd., based in Malahide, provided the independent validation of mission critical software (independent software validation facility or SVF) and developed the software for the communications interface between the orbiter and the lander. Captec also provided engineering support to the prime contractor for the launch activities at Kourou. Space Technology Ireland Ltd. at Maynooth University has designed, constructed and tested the Electrical Support System Processor Unit (ESS) for the Rosetta mission. ESS stores, transmits and provides decoding for the command streams passing from the spacecraft to the lander and handles the data streams coming back from the scientific experiments on the lander to the spacecraft.

 * Italy
 * The Italian Space Agency (ASI) developed the SD2 instrument and the photovoltaic assembly. Italian Alenia Space was involved in the assembly, integration and testing of the probe, as well as several mechanical and electrical ground support equipment. The company also built the probe's S-band and X-band digital transponder, used for communications with Earth.

 * Netherlands
 * Moog Bradford (Heerle, The Netherlands) provided the Active Descent System, which guided and propelled the lander down to its landing zone. To accomplish the ADS, a strategic industrial team was formed with Bleuler-Baumer Mechanik in Switzerland.

 * Poland
 * The Space Research Centre of the Polish Academy of Sciences built the Multi-Purpose Sensors for Surface and Subsurface Science (MUPUS).

 * Spain
 * The GMV Spanish division has been responsible for the maintenance of the calculation tools to calculate the criteria of lighting and visibility necessary to decide the point of landing on the comet, as well as the possible trajectories of decline of the Philae module. Other important Spanish companies or educational institutions that have been contributed are as follows: INTA, Airbus Defence and Space Spanish division, other small companies also participated in subcontracted packages in structural mechanics and thermal control like AASpace (former Space Contact), and the Universidad Politécnica de Madrid.

 * Switzerland
 * The Swiss Centre for Electronics and Microtechnology developed CIVA.

 * United Kingdom
 * The Open University and the Rutherford Appleton Laboratory (RAL) developed PTOLEMY. RAL also constructed the blankets that kept the lander warm throughout its mission. Surrey Satellites Technology Ltd. (SSTL) constructed the momentum wheel for the lander. It stabilised the module during the descent and landing phases. Manufacturer e2v supplied the CIVA and Rolis camera systems used to film the descent and take images of samples, as well as three other camera systems.

Media coverage
The landing was featured heavily in social media, with the lander having an official Twitter account portraying a personification of the spacecraft. The hashtag "#CometLanding" gained widespread traction. A Livestream of the control centres was set up, as were multiple official and unofficial events around the world to follow Philae landing on Churyumov–Gerasimenko. Various instruments on Philae were given their own Twitter accounts to announce news and science results.

Popular culture
Vangelis composed the music for the trio of music videos released by ESA to celebrate the first-ever attempted soft landing on a comet by ESA's Rosetta mission.

On 12 November 2014, the search engine Google featured a Google Doodle of Philae on its home page. On 31 December 2014, Google featured Philae again as part of its New Year's Eve 2014 Doodle.

Online comic author Randall Munroe wrote a live updating strip on his website xkcd on the day of the landing.

title: Philae (spacecraft)


text:
TSA (disambiguation)

The Transportation Security Administration is an American transportation safety organization.

TSA may also refer to:

Organizations

 * Technology Student Association
 * Tenant Services Authority, a former regulatory body in England
 * Thailand Swimming Association, the governing body for aquatic sports in Thailand
 * Theosophical Society in America
 * The Scout Association, a UK scouting organisation
 * The Sports Authority, former name of the defunct sports retailer Sports Authority
 * Tourette Syndrome Association, former name of the Tourette Association of America
 * Transpacific Stabilization Agreement, a research and discussion forum for the main transpacific container shipping lines
 * Trans States Airlines, US
 * Turkish Space Agency, a government agency for national aerospace research in Turkey
 * The Salvation Army

Education

 * Tattnall Square Academy, Macon, Georgia, US
 * Thinking Skills Assessment, a generic university admissions test
 * Tiong Se Academy, Chinese school, the Philippines
 * The Sharon Academy, Vermont, US
 * Territory-wide System Assessment, a Hong Kong academic assessment program
 * Tulane School of Architecture, New Orleans, Louisiana, US
 * Toledo School for the Arts, a public charter school in Toledo, Ohio

Places

 * Taipei Songshan Airport (IATA code)
 * Tin Sau stop, Hong Kong (MTR station code)
 * Titanium Security Arena, a sports stadium in Australia

Science and technology

 * TS/A, a mouse mammary carcinoma cell line
 * Temperature swing adsorption, a gas separation technique
 * Time Stamping Authority, carrying out cryptographic trusted timestamping
 * Trichostatin A, an inhibitor of histone deacetylases
 * Trypticase soy agar, a common laboratory plating media
 * Tumor-specific antigen

Arts and entertainment

 * TSA (band) (Tajne Stowarzyszenie Abstynentów or Teetotallers' Secret Association), a Polish heavy metal/hard rock band
 * Transformation Story Archive, web site archiving amateur fiction
 * Toilet Safety Administration, parody of US Transportation Security Administration in TV episode "Reverse Cowgirl" (South Park)

Other uses

 * Tax sheltered annuity or 403(b) plan
 * Technicien supérieur de l'aviation, a certification in French civil aviation
 * Treasury single account, a financial policy in Nigeria

title: TSA (disambiguation)


text:
Grand Canyon of the Yellowstone

The Grand Canyon of the Yellowstone is the first large canyon on the Yellowstone River downstream from Yellowstone Falls in Yellowstone National Park in Wyoming. The canyon is approximately 24 mi long, between 800 and 1200 ft deep and from 0.25 to 0.75 mi wide.

History
Although trappers and prospectors who visited the Yellowstone region had knowledge of the canyon, the first significant descriptions were publicized after the Cook–Folsom–Peterson Expedition of 1869 and the Washburn-Langford-Doane Expedition of 1870.

When Charles W. Cook first viewed the canyon after traveling west from the Lamar Valley on September 20, 1869, he subsequently wrote these words in his journal:

"I was riding ahead, the two pack animals following, and then Mr. Folsom and Mr. Peterson on their saddle horses. I remembered seeing what appeared to be an opening in the forest ahead, which I presumed to be a park, or open country. While my attention was attracted by the pack animals, which had stopped to eat grass, my saddle horse suddenly stopped.  I turned and looked forward from the brink of the great canyon, at a point just across from what is now called Inspiration Point.  I sat there in amazement, while my companions came up, and after that, it seemed to me that it was five minutes before anyone spoke."

A year later during the Washburn expedition, on August 30–31, 1870, Lt. Gustavus C. Doane described the canyon with a bit more scientific detail:

"As we approached the Grand Cañon a dull roaring sound warned us that the falls were near at hand. ... I had descended the cañon at a point where the creek joined the river, precipitated into a gorge just above its juncture in a lovely cascade of three falls, in the aggregate 100 feet in height. This was named Crystal Cascade, and the stream Cascade Creek. In the bed of the gorge were to be found an infinite variety of volcanic specimens, quartz, feldspar, mica, granites, lavas, basalts, composite crystals; in fact, everything, from asbestos to obsidian, was represented by fragments in the bed of this stream. There were also beautiful clay stone specimens, of which we afterward learned the origin. At the foot of the gorge and on the margin of the Yellowstone stood a high promontory of concretionary lava, literally filled with volcanic butternuts. Many of these were loose, and could be taken out of the rock with the hand; broken open they were invariably hollow, and lined with minute quartz crystals of various tints. This formation is rare, but occurs frequently in the great basin. From the outer point of this promontory can be seen the foot of the upper fall of the Yellowstone, and I climbed to the summit to obtain a view.

In scenic beauty, the upper cataract far excels the lower. It has life, animation, while the lower one simply follows its channel; both, however, are eclipsed, as it were, by the singular wonders of the mighty cañon below. This deepens rapidly; the stream flowing over rapids continually. ... Several of the party descended into the chasm a short distance below the fall, but could not reach its foot. ... The walls of the cañon are of gypsum, in some places having an incrustation of lime white as snow, from which the reflected rays of the sun produce a dazzling effect, rendering it painful to look into the gulf. In others the rock is crystalline and almost wholly sulphur, of a dark yellow color, with streaks of red, green and black, caused by the percolations of hot mineral waters, of which thousands of springs are seen, in many instances, flowing from spouts high up on the walls on either side. The combinations of metallic lusters in the coloring of the walls is truly wonderful, surpassing, doubtless, anything of the kind on the face of the globe. The ground slopes to the cañon on the opposite or east side, and from it to the low valley on the west. Three miles below the fall the chasm is 1,050 feet deep. In some places masses of the rock have crumbled and slid down in a talus of loose material at the foot; in others, promontories stand out in all manner of fantastic forms, affording vistas of wonder utterly beyond the power of description. On the caps of these dizzy heights, mountain sheep and elk rest during the night. ... We had come down the ravine at least four miles, and looking upward the fearful wall appeared to reach the sky. It was about 3 o'clock p.m., and stars could be distinctly seen, so much of the sunlight was cut off from entering the chasm. Tall pines on the extreme verge appeared the height of two or three feet. The cañon, as before said, was in two benches, with a plateau on either side, about half way down. This plateau, about a hundred yards in width, looked from below like a mere shelf against the wall; the total depth was not less than 2,500 feet, and more probably 3,000. There are perhaps other canons longer and deeper than this one, but surely none combining grandeur and immensity with peculiarity of formation and profusion of volcanic or chemical phenomena."

In 1890, Bozeman resident H.F. Richardson (known as Uncle Tom) was given a permit to operate a ferry across the Yellowstone River near the site of today's Chittenden Memorial Bridge and take tourists down into the canyon below the lower falls on Uncle Tom's Trail. Although the original trail no longer exists, there is still a steep stairway down to the base of the lower falls that is called Uncle Tom's Trail.  Uncle Tom's Trail is approximately a 3-mile hike.

Geology
The specifics of the geology of the canyon are not well understood, except that it is the result of erosion by the Yellowstone River, not by glaciation. After the Yellowstone Caldera eruption of about 600,000 years ago, the area was covered by a series of lava flows. The area was also faulted by the doming action of the caldera before the eruption. The site of the present canyon, as well as any previous canyons, was probably the result of this uplift and related faulting, which allowed erosion to proceed at an accelerated rate. The area was also covered by the glaciers that formed during several ice ages. Glacial deposits probably filled the canyon at one time, but have since been eroded away, leaving little or no evidence of their presence.

The canyon below the Lower Yellowstone Falls was at one time the site of a geyser basin that was the result of rhyolite lava flows, extensive faulting, and heat beneath the surface (related to the hot spot). No one is sure exactly when the geyser basin was formed in the area, although it was probably present at the time of the last glaciation. The chemical and heat action of the geyser basin caused the rhyolite rock to become hydrothermally altered, making it very soft and brittle and more easily erodible (sometimes likened to baking a potato). Evidence of this thermal activity still exists in the canyon in the form of geysers and hot springs that are still active and visible. The Clear Lake area, which is fed by hot springs, south of the canyon is probably also a remnant of this activity. According to Ken Pierce, U.S. Geological Survey geologist, at the end of the last glacial period, about 14,000 to 18,000 years ago, ice dams formed at the mouth of Yellowstone Lake. When the ice dams melted, a great volume of water was released downstream causing massive flash floods and immediate and catastrophic erosion of the present-day canyon. These flash floods probably happened more than once. The canyon is a classic V-shaped valley, indicative of river-type erosion rather than glaciation. Today the canyon is still being eroded by the Yellowstone River.

The colors in the canyon are also a result of hydrothermal alteration. The rhyolite in the canyon contains a variety of different iron compounds. When the old geyser basin was active, the "cooking" of the rock caused chemical alterations in these iron compounds. Exposure to the elements caused the rocks to change colors. The rocks are oxidizing; in effect, the canyon is rusting. The colors indicate the presence or absence of water in the individual iron compounds. Most of the yellows in the canyon are the result of iron present in the rock.

title: Grand Canyon of the Yellowstone


text:
Billy Bailey

Billy Bailey (January 1947 – January 25, 1996) was a convicted murderer who was hanged in Delaware in 1996. He became the third person to be hanged in the United States since 1965 (the previous two were Charles Rodman Campbell and Westley Allan Dodd, both in Washington), and the first person hanged in Delaware in 50 years. As of 2024, he remains the last person to be lawfully executed by hanging in the United States.

Early life
The ninth of 23 children, Bailey lived in stark poverty and suffered chronic physical abuse, state records show. His mother died when he was less than a year old. As an adult, Bailey was known to police as a brawler and a thief.

The crime
In 1979, after being convicted of forgery, Bailey was assigned to the Plummer House, a work release facility in Wilmington, Delaware, but soon escaped. He later appeared at the home of his foster sister, Sue Ann Coker, in Cheswold, Delaware, saying he was upset and was not going back to the Plummer House.

He and Charles Coker, his foster sister's husband, went on an errand in Coker's truck. Bailey asked Coker to stop at a liquor store. Bailey entered the store and robbed the clerk at gunpoint. Emerging from the store with a pistol in one hand and a bottle in the other, Bailey told Coker that the police would be arriving, and asked to be dropped at Lambertson's Corner, about 1.5 mi away.

At Lambertson's Corner, Bailey entered the farmhouse of Gilbert Lambertson, aged 80, and his wife, Clara Lambertson, aged 73. Bailey shot Gilbert Lambertson twice in the chest with a pistol, and once in the head with the Lambertsons' shotgun. He also shot Clara Lambertson once in the shoulder with the pistol, and once each in the abdomen and neck with the shotgun. Both Lambertsons died. Bailey arranged their bodies in chairs, and then fled from the scene. He was spotted by a Delaware State Police helicopter as he ran across the Lambertsons' field. He attempted to shoot the helicopter co-pilot with the pistol, and was later arrested.

Conviction
Bailey was found guilty of the murders in 1980. After his conviction, the jury found that his crimes "were outrageously or wantonly vile, horrible, or inhuman", and recommended a death sentence. Bailey was sentenced to be hanged by his neck until dead.

Preparations
Although the method of execution in Delaware had been changed to lethal injection in 1986, he had the legal option of choosing to be hanged instead. Bailey refused to accept lethal injection, telling a visitor, "I'm not going to let them put me to sleep."

As Delaware had not carried out a hanging in 50 years, state officials sought advice from corrections officials at Washington State Penitentiary in Walla Walla, Washington, where hangings had recently been performed.

The wooden gallows were built on the grounds of the Delaware Correctional Center at Smyrna in 1986. The structure required renovation and strengthening before Bailey could be executed on it. The platform housing the trap door was 15 ft from the ground and accessed by 23 steps.

Delaware used an execution protocol written by Fred Leuchter. Leuchter's protocol specified the use of 30 ft of 0.75 in diameter Manila hemp rope, boiled to take out stretch and any tendency to coil. The length of the rope sliding inside the knot was lubricated with melted paraffin wax, to allow it to slide freely. A black hood was specified by the protocol, as was a sandbag to test the trap door and a "collapse board" to which a prisoner could be strapped if necessary.

The day before, Bailey was weighed at 220 lb, and the drop was determined to be around 5 ft.

Bailey was moved from his prison cell to the execution trailer used for lethal injection prior to the execution. There, he spent his last 24 hours, sleeping, eating, watching television, talking with staff, and meeting with his fifty-three-year-old sister, Betty Odom, the prison chaplain, and his attorney. For his last meal, he requested a well-done steak, a baked potato with sour cream and butter, buttered rolls, peas, and vanilla ice cream.

His final appeals having failed, Bailey was executed on January 25, 1996. The gallows in Delaware were dismantled in 2003, because from that year, none of its death row inmates remained eligible to choose hanging over lethal injection.

title: Billy Bailey


text:
Thrombopoietin

Thrombopoietin (THPO) also known as megakaryocyte growth and development factor (MGDF) is a protein that in humans is encoded by the THPO gene.

Thrombopoietin is a glycoprotein hormone produced by the liver and kidney which regulates the production of platelets. It stimulates the production and differentiation of megakaryocytes, the bone marrow cells that bud off large numbers of platelets.

Megakaryocytopoiesis is the cellular development process that leads to platelet production. The protein encoded by this gene is a humoral growth factor necessary for megakaryocyte proliferation and maturation, as well as for thrombopoiesis. This protein is the ligand for MLP/C_MPL, the product of myeloproliferative leukemia virus oncogene.

Genetics
The thrombopoietin gene is located on the long arm of chromosome 3 (q26.3-27). Abnormalities in this gene occur in some hereditary forms of thrombocytosis (high platelet count) and in some cases of leukemia. The first 155 amino acids of the protein share homology with erythropoietin.

Function and regulation
Thrombopoietin is produced in the liver by both parenchymal cells and sinusoidal endothelial cells, as well as in the kidney by proximal convoluted tubule cells. Small amounts are also made by striated muscle and bone marrow stromal cells. In the liver, its production is augmented by interleukin 6 (IL-6). However, the liver and the kidney are the primary sites of thrombopoietin production.

Thrombopoietin regulates the differentiation of megakaryocytes and platelets, but studies on the removal of the thrombopoietin receptor show that its effects on hematopoiesis are more versatile.

Its negative feedback is different from that of most hormones in endocrinology: The effector regulates the hormone directly. Thrombopoietin is bound to the surface of platelets and megakaryocytes by the mpl receptor (CD 110). Inside the platelets it gets destroyed, while inside the megakaryocytes it gives the signal of their maturation and consecutively more platelet production. The bounding of the hormone at these cells thereby reduces further megakaryocyte exposure to the hormone. Therefore, the rising and dropping platelet and megakaryocyte concentrations regulate the thrombopoietin levels. Low platelets and megakaryocytes lead a higher degree of thrombopoietin exposure to the undifferentiated bone marrow cells, leading to differentiation into megakaryocytes and further maturation of these cells. On the other hand, high platelet and megakaryocyte concentrations lead to more thrombopoetin destruction and thus less availability of thrombopoietin to bone marrow.

TPO, like EPO, plays a role in brain development. It promotes apoptosis of newly generated neurons, an effect counteracted by EPO and neurotrophins.

Therapeutic use
Despite numerous trials, thrombopoietin has not been found to be useful therapeutically. Theoretical uses include the procurement of platelets for donation, and recovery of platelet counts after myelosuppressive chemotherapy.

Trials of a modified recombinant form, megakaryocyte growth and differentiation factor (MGDF), were stopped when healthy volunteers developed autoantibodies to endogenous thrombopoietin and then developed thrombocytopenia. Romiplostim and Eltrombopag, structurally different compounds that stimulate the same pathway, are used instead.

A quadrivalent peptide analogue is being investigated, as well as several small-molecule agents, and several non-peptide ligands of c-Mpl, which act as thrombopoietin analogues.

Discovery
Thrombopoietin was cloned by five independent teams in 1994. Before its identification, its function has been hypothesized for as much as 30 years as being linked to the cell surface receptor c-Mpl, and in older publications thrombopoietin is described as c-Mpl ligand (the agent that binds to the c-Mpl molecule). Thrombopoietin is one of the Class I hematopoietic cytokines.

title: Thrombopoietin


text:
Wooster

Wooster may refer to:

India

 * Wooster Nagar, a small fishing village in the state of Tamil Nadu

United States

 * Wooster, Arkansas, a town in Faulkner County
 * Wooster, Georgia, an unincorporated community
 * Wooster, Kosciusko County, Indiana, an unincorporated community
 * Wooster, Scott County, Indiana, an unincorporated community
 * Wooster, Ohio, a city in Wayne County
 * Wooster, Baytown, Texas
 * Wooster Square, a neighborhood in the city of New Haven, Connecticut
 * Wooster Township, Wayne County, Ohio

Schools in the United States

 * College of Wooster, in Wooster, Ohio
 * Earl Wooster High School, in Reno, Nevada
 * Wooster High School (Ohio), in Wooster, Ohio
 * Wooster School, in Danbury, Connecticut

Groups and organizations

 * Wooster Collective, an online street art website
 * The Wooster Group, a New York-based U.S. ensemble of theatre and media artists
 * Wooster Warriors, a former U.S. ice hockey team

Other uses

 * Wooster Island, an island in the Housatonic River in Orange, Connecticut
 * Wooster Lake, a lake in Lake County, Illinois

People with the surname Wooster

 * Charles Whiting Wooster, 1780-1848, grandson of David Wooster and Commander-in-Chief of the Chilean Navy
 * David Wooster (1710–1777), brigadier-general in the Continental Army during the American Revolution
 * Edward Wooster (1622–1689), early pioneer and founder of Derby, Connecticut
 * Fred Wooster (1938–1993), cofounder of the Saanich Lacrosse Association, Canadian Lacrosse Hall of Fame
 * Louise Wooster (1842–1913), "Lou Wooster", famous madam in Birmingham, Alabama
 * Reginald Wooster (1903-1968), English cricketer who made one first-class appearance for Northamptonshire
 * Stanton Hall Wooster of Wooster and Davis, a U.S. Navy airman who attempted to fly over the Atlantic Ocean in 1927

Fictional characters

 * Bertie Wooster, character in the stories of P. G. Wodehouse, adapted in the Jeeves and Wooster TV show
 * Henry Wooster, character in the stories of P. G. Wodehouse, uncle of Bertie Wooster
 * Wooster, a giant weasel in The New Adventures of Winnie the Pooh episode, The Great Honey Pot Robbery

title: Wooster


text:
User talk:Musashiwashi

Hi!
I'd like to see things like "Musashiwashi, you did a really brilliant job with this article" here, but if you really want to argue that's also fine with me. - MW, 15 Mar 2004, 21:46 UTC

title: User talk:Musashiwashi


text:
Monier Monier-Williams

Sir Monier Monier-Williams (né Williams; 12 November 1819 – 11 April 1899) was a British scholar who was the second Boden Professor of Sanskrit at Oxford University, England. He studied, documented and taught Asian languages, especially Sanskrit, Persian and Hindustani.

Early life
Monier Williams was born in Bombay, the son of Colonel Monier Williams, surveyor-general in the Bombay presidency. His surname was "Williams" until 1887, when he added his given name to his surname to create the hyphenated "Monier-Williams". In 1822, he was sent to England to be educated at private schools at Hove, Chelsea and Finchley. He was educated at King's College School, Balliol College, Oxford (1838–40), the East India Company College (1840–41) and University College, Oxford (1841–44). He took a fourth-class honours degree in Literae Humaniores in 1844.

He married Julia Grantham in 1848. They had six sons and one daughter. He died, aged 79, in Cannes, France.

In 1874 he bought and lived in Enfield House, Ventnor, on the Isle of Wight where he and his family lived until at least 1881. (The 1881 census records the occupant was 61-year-old Professor Monier Monier-Williams; his wife, Julia; and two children, Montague (20) and Ella (22).)

Career
Monier Williams taught Asian languages at the East India Company College from 1844 until 1858 when company rule in India ended after the 1857 rebellion. He came to national prominence during the 1860 election campaign for the Boden Chair of Sanskrit at Oxford University, in which he stood against Max Müller.

The vacancy followed the death of Horace Hayman Wilson in 1860. Wilson had started the university's collection of Sanskrit manuscripts upon taking the chair in 1831, and had indicated his preference that Williams should be his successor. The campaign was notoriously acrimonious. Müller was known for his liberal religious views and his philosophical speculations based on his reading of Vedic literature. Monier Williams was seen as a less brilliant scholar, but had a detailed practical knowledge of India itself, and of actual religious practices in modern Hinduism. Müller, in contrast, had never visited India.

Both candidates had to emphasise their support for Christian evangelisation in India, since that was the basis on which the professorship had been funded by its founder. Monier Williams' dedication to Christianisation was not doubted, unlike Müller's. Monier Williams also stated that his aims were practical rather than speculative. "Englishmen are too practical to study a language very philosophically", he wrote.

After his appointment to the professorship Williams declared from the outset that the conversion of India to the Christian religion should be one of the aims of orientalist scholarship. In his book Hinduism, published by SPCK in 1877, he predicted the demise of the Hindu religion and called for Christian evangelism to ward off the spread of Islam. According to Saurabh Dube this work is "widely credited to have introduced the term Hinduism into general English usage" while David N. Lorenzen cites the book along with India, and India Missions: Including Sketches of the Gigantic System of Hinduism, Both in Theory and Practice : Also Notices of Some of the Principal Agencies Employed in Conducting the Process of Indian Evangelization

Writings and foundations

When Monier Williams founded the University's Indian Institute in 1883, it provided both an academic focus and also a training ground for the Indian Civil Service. Since the early 1870s Monier Williams planned this institution. His vision was the better acquaintance of England and India. On this account he supported academic research into Indian culture. Monier Williams travelled to India in 1875, 1876 and 1883 to finance his project by fundraising. He gained the support of Indian native princes. In 1883 the Prince of Wales laid the foundation stone; the building was inaugurated in 1896 by Lord George Hamilton. The Institute closed on Indian independence in 1947.

In his writings on Hinduism Monier Williams argued that the Advaita Vedanta system best represented the Vedic ideal and was the "highest way to salvation" in Hinduism. He considered the more popular traditions of karma and bhakti to be of lesser spiritual value. However, he argued that Hinduism is a complex "huge polygon or irregular multilateral figure" that was unified by Sanskrit literature. He stated that "no description of Hinduism can be exhaustive which does not touch on almost every religious and philosophical idea that the world has ever known."

Monier-Williams compiled a Sanskrit–English dictionary, based on the earlier Petersburg Sanskrit Dictionary, which was published in 1872. A later revised edition was published in 1899 with collaboration by Ernst Leumann and Carl Cappeller (sv).

Honours
He was knighted in 1876, and was made KCIE in 1887, when he adopted his given name of Monier as an additional surname. He was elected as a member of the American Philosophical Society in 1886.

He also received the following academic honours: Honorary DCL, Oxford, 1875; LLD, Calcutta, 1876; Fellow of Balliol College, Oxford, 1880; Honorary PhD, Göttingen, 1880s; Vice-President, Royal Asiatic Society, 1890; Honorary Fellow of University College, Oxford, 1892.

Translations
Monier-Williams's translations include that of Kālidāsa's plays Vikramorvasi (1849) and Śākuntala (1853; 2nd ed. 1876).

 * Translation of Shakuntala (1853)
 * Hindu Literature: comprising the Book of Good Counsels, Nala and Damayanti, the Rámáyana and Śakoontalá

Original works

 * Original papers illustrating the history of the application of the Roman alphabet to the languages of India: Edited by Monier Williams (1859) Modern Reprint
 * Translation of Shikshapatri – The manuscript of the principal scripture Sir John Malcolm received from Swaminarayan on 26 February 1830 when he was serving as the Governor of Bombay Presidency, Imperial India. Currently preserved at Bodleian Library.
 * Brahmanism and Hinduism (1883)
 * Buddhism, in its connexion with Brahmanism and Hinduism, and in its contrast with Christianity (1889)
 * Sanskrit-English Dictionary, ISBN 0-19-864308-X.
 * A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European languages, Monier Monier-Williams, revised by E. Leumann, C. Cappeller, et al. 1899, Clarendon Press, Oxford
 * A Practical Grammar of the Sanskrit Language, Arranged with Reference to the Classical Languages of Europe, for the Use of English Students, Oxford: Clarendon, 1857, enlarged and improved Fourth Edition 1887
 * Buddhism, in its connexion with Brahmanism and Hinduism, and in its contrast with Christianity (1889)
 * Sanskrit-English Dictionary, ISBN 0-19-864308-X.
 * A Sanskrit-English Dictionary: Etymologically and Philologically Arranged with Special Reference to Cognate Indo-European languages, Monier Monier-Williams, revised by E. Leumann, C. Cappeller, et al. 1899, Clarendon Press, Oxford
 * A Practical Grammar of the Sanskrit Language, Arranged with Reference to the Classical Languages of Europe, for the Use of English Students, Oxford: Clarendon, 1857, enlarged and improved Fourth Edition 1887

title: Monier Monier-Williams


text:
Technology Student Association

The Technology Student Association (TSA) is a national student organization created to develop skills in science, technology, engineering, and mathematics (STEM) and business education. TSA's aim is to develop leadership, academic, and business management skills in the workplace among students and leaders within the community. The organization has over 300,000 members.

Competition
Competitive events are separated into middle school and high school levels, with students competing only with their respective age group. Competitions take place at the local, regional, state, and national level. A component of leadership is often entailed in events at both levels, with some events being devoted to leadership (such as Leadership Strategies MS).

All TSA competitions are correlated with national science, technology, engineering and mathematics and business standards. Sample middle school events include Biotechnology, Career Prep, Video Game Design, and Inventions and Innovations. High school events include Animatronics, Computer Aided Design (CAD), Dragster Design, Promotional Design, System Control Technology, Flight Endurance, Software Development, and Webmaster. For the 2022–2023 season Audio Podcasting, Drone Challenge (UAV), and Virtual Reality Visualization were added as high school events and the Cybersecurity event was removed.

Scores are based upon a nationally developed rubric. Winners are chosen based on these scores. In many events, semi-finalists (top 12) move onto a second round of competition which usually involves an interview with the judges about the project. First, second, and third-place winners are awarded a trophy, and finalists (top 10) are recognized at the national level.

Program initiatives
The Technology Student Association has partnered with many groups to promote other skills. Junior Solar Sprint is a national program allows students to design solar-powered cars. Tests of Engineering Aptitude, Mathematics, and Science (TEAMS) is an annual one-day competition. TSA has partnered with the VEX Robotics Competition to allow students to design and create robots to complete specific tasks. UNITE is a summer program funded by the U.S. Army Research Office that encourages high school students to pursue engineering careers. Every TSA middle school and high school member is required to submit LEAP (Leadership. Education. Achievement. Personal Growth.) documentation as part of every competition in which they compete. LEAP documentation tracks the leadership activities and experiences a TSA member has completed as part of each competition.

History
TSA became an independent organization in 1978, when AIASA Inc. was formed to oversee the activities of the American Industrial Arts Student Association. Between the foundation of AIASA as an independent organization (it had formerly been a part of the American Industrial Arts Association) and 1988, the association grew and began to take shape.

In 1988, the AIASA changed its name to the Technology Student Association as part of a shift in focus from industrial arts to mainstream technology. This action followed a similar name change by the Texas state delegation the previous year. In 1989, the official logo, submitted by a chapter advisor, was adopted. In 1990, the logo received a trademark from the U.S. Patent and Trademark Office.

Today, the association has grown to include more than 300,000 members in more than 2,300 secondary schools across 48 states. It has established an Honor Society, manages numerous competitive events and has partnerships with several organizations. Since TSA was chartered in 1978, more than five million students have participated as members.

As part of its national service project, TSA has a partnership with the American Cancer Society (ACS). TSA members raise money to help fund research, education, advocacy, and patient support. The ACS presents Spirit of Service awards to chapters that participate in fundraising.

National conferences
Students elect a National Officer team annually at the Technology Student Association national conference. The 2023 national conference was held at the Kentucky International Convention Center in Louisville, Kentucky. The 2024 national conference will be held at the Rosen Shingle Creek Resort in Orlando, Florida.

Notable alumni

 * Hunter Hayes - Country singer and music star, Tennessee TSA
 * Andy Hertzfeld - Member of the original Macintosh development team and computer entrepreneur
 * Chad Hurley - Co-founder of YouTube, Pennsylvania TSA
 * Sal Khan - Founder of Khan Academy, Louisiana TSA
 * Carrie Underwood - Country singer and music star, Oklahoma TSA
 * Mark Zuckerberg - Founder of Facebook, New York TSA
 * Rep. Maxwell Frost - United States Congressman (FL-10), Florida TSA

title: Technology Student Association


text:
Davíð Stefánsson

Davíð Stefánsson (21 January 1895 – 1 March 1964) from Fagriskógur was a popular Icelandic poet and novelist, best known for his ten volumes of poetry.

He was born on 21 January 1895, in Fagriskógur, Eyjafjördur, Iceland and he died on 1 March 1964, in Akureyri Iceland.

Davíð Stefánsson came of a cultured yeoman family and was brought up with a love for his homeland, its literature, and its folklore. He frequently journeyed abroad but lived most of his life in the town of Akureyri, where he was a librarian (1925–52).

Novels and plays
In 1926, he wrote Munkarnir á Möðruvöllum ("The Monks of Möðruvellir") and in 1941, the powerful novel Sólon Islandus (I - II), a novel about Sölvi Helgason, a daydreaming 19th-century vagabond whose intellectual ambitions are smothered by society.

In 1941, he wrote the successful play, Gullna hliðið ("The Golden Gate") and in 1944, Vopn guðanna ("Weapons of the Gods") and in 1953, his play Landið gleymda ("The Forgotten Country").

Poetry
Stefánsson's early poetry, including most of his folk themes and love lyrics, appeared in:
 * 1919: Svartar fjaðrir ("Black Feathers")
 * 1922: Kvæði ("Poems")
 * 1924: Kveðjur ("Greetings")
 * 1929: Ný Kvæði ("New Poems")

They were combined and published as a collected volume in 1930.

His later poetry—darkening in social satire, reformatory zeal against capitalism and organized religion, and despair over the war—was published as:
 * 1933: Í byggðum ("Among Human Habitations")
 * 1936: Að norðan ("From the North")
 * 1947: Ný kvæðabók ("A New Book of Poems")
 * 1966: Síðustu ljóð ("Last Poems") (posthumously)

title: Davíð Stefánsson


text:
Self-destruct

A self-destruct is a mechanism that can cause an object to destroy itself or render itself inoperable after a predefined set of circumstances has occurred.

Self-destruct mechanisms are typically found on devices and systems where malfunction could endanger large numbers of people.

Land mines
Some types of modern land mines are designed to self-destruct, or chemically render themselves inert after a period of weeks or months to reduce the likelihood of friendly casualties during the conflict or civilian casualties after the conflict's end. The Amended Protocol II to the Convention on Certain Conventional Weapons (CCW), amended in 1996, requires that anti-personnel land mines deactivate and self-destruct, and sets standards for both. Landmines currently used by the United States military are designed to self-destruct after between 4 hours and 15 days depending upon the type. The landmines have a battery and when the battery dies, the land mine self-destructs. The self-destruct system never failed in over 67,000 tested landmines in a variety of conditions. Not all self-destruct mechanisms are absolutely reliable, and most landmines that have been laid throughout history are not equipped to self-destruct. Landmines can also be designed to self-deactivate, for instance by a battery running out of a charge, but deactivation is considered a different mechanism from self-destruction.

Military ships
Another form of a self-destruct system can be seen in the naval procedure of scuttling, which is used to destroy a ship or ships to prevent them from being seized and/or reverse engineered.

Generally the scuttling of a ship uses strategically-placed explosive charges by a demolition crew and/or the deliberate cutting open of the hull rather than an in-built self-destruct system.

Rockets
Launch vehicles self-destruct when they go errant, to prevent the endangerment of nearby ground personnel, spectators, buildings and infrastructure. When a rocket flies outside of a prescribed safety zone, personnel monitoring the launch or onboard computers activate the rocket's flight termination system. This usually detonates explosives mounted on the rocket, which sever its propellant tanks or solid fuel casing, leading to a controlled breakup of the vehicle.

Anti-aircraft cannon shells
Since anti-aircraft weapons are used in the home front or in the rear of friendly forces anti-aircraft cannon shells are often equipped with self-destruct mechanisms to prevent missed shots from falling down and causing damage to friendly targets. Different self-destruct types exists: in tracer ammunition the burning tracer material can trigger a self-destruct fuse at the end. Other self-destruct types are mechanical where a spring is held back by the centrifugal force of the rotating projectile; as the drag slows down the rotation the force is eventually no longer able to prevent the spring from triggering the self-destruct fuse. Heavy anti-aircraft cannons typically fired time fused shells which did not need a separate self-destruct since they were intended to detonate in the air after a set time.

Deep-sea oil drilling
A form of self-destruct system can also be observed in deep-sea oil drilling. In the event of an oil well becoming disconnected from its oil rig, a dead man's switch may trigger activation of a blowout preventer blind shear ram, which cuts the drill pipe and permanently seals the well to prevent an oil leak. The oil spill that followed the Deepwater Horizon explosion is an example where the self-destruct system failed to operate correctly (due to the pipe buckling and moving outside of the blind shear ram's reach).

Data storage
Self-destruct mechanisms are sometimes employed to prevent an apparatus or information from being used by unauthorized persons in the event of loss or capture. For example, they may be found in high-security data storage devices (e.g. IronKey), where it is important for the data to be destroyed to prevent compromise.

Similarly, some online social media platforms are equipped with a Stories feature, where posted content is automatically erased after a predetermined time, commonly 24 hours. This concept has been popularized by Snapchat and later adapted by Instagram and YouTube.

Artwork
Some artworks may have mechanisms in them to destruct themselves in front of many eyes watching. An example is the painting Love is in the Bin by Banksy, which shredded itself right after a £1 million auction at Sotheby's London on 5 October 2018.

Use in fiction
In the 1960s television series The Man from U.N.C.L.E. and Mission: Impossible, sensitive intelligence or equipment is shown to self-destruct in order to prevent it from falling into enemy hands. Notably, the usage of "self-destruct" as a verb is said to have been coined on Mission: Impossible.

Self-destruct mechanisms are frequent plot devices in science fiction stories, such as those in the Star Trek or Alien fictional universes. They are generally found on military installations and starships too valuable to allow an enemy to capture. In many such stories, these mechanisms not only obliterate the object protected by the device, but cause massive destruction in a large surrounding area. Often, the characters have a limited amount of time to escape the destruction, or to disable the mechanism, creating story tension. In some cases, an artificial intelligence will invoke self-destruct due to cognitive dissonance.

Usually the method required to initiate a self-destruct sequence is lengthy and complex, as in Alien, or else requires multiple officers aboard the ship with individual passcodes to concur, while audible and/or visible countdown timers allow audiences to track the growing urgency of the characters' escape. Passwords in 1970s and 1980s movies are often clearly insecure for their purposes as self-destruct triggers, considering accounts with even low-level security—let alone the high-security measures which would come for a self-destruct mechanism—in modern times generally have far more complex password requirements (the writers of the era not anticipating the issues soon to be raised by the easy affordability of fast computer hardware for conducting brute-force attacks).

title: Self-destruct


text:
User talk:Arvind Singh

Hello Arvind, welcome to Wikipedia! I hope you like the place and decide to stay. Drop us a note at the new user log so that we can meet you and help you get started. If you need editing help, visit How does one edit a page. For format questions, visit our manual of style. If you have any other questions about the project then check out Help or add a question to the village pump.

Again, welcome! ugen64 22:12, Mar 13, 2004 (UTC)

Wikipedia:Indian wikipedians' notice board
Hi Arvind. I would like you to be an active member of Indian wikipedians' notice board. utcursch 07:02, Dec 29, 2004 (UTC)

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title: User talk:Arvind Singh


text:
Clique (graph theory)

In the mathematical area of graph theory, a clique ( or ) is a subset of vertices of an undirected graph such that every two distinct vertices in the clique are adjacent. That is, a clique of a graph $$G$$ is an induced subgraph of $$G$$ that is complete. Cliques are one of the basic concepts of graph theory and are used in many other mathematical problems and constructions on graphs. Cliques have also been studied in computer science: the task of finding whether there is a clique of a given size in a graph (the clique problem) is NP-complete, but despite this hardness result, many algorithms for finding cliques have been studied.

Although the study of complete subgraphs goes back at least to the graph-theoretic reformulation of Ramsey theory by, the term clique comes from , who used complete subgraphs in social networks to model cliques of people; that is, groups of people all of whom know each other. Cliques have many other applications in the sciences and particularly in bioinformatics.

Definitions
A clique, $C$, in an undirected graph $G = (V, E)$ is a subset of the vertices, $C ⊆ V$, such that every two distinct vertices are adjacent. This is equivalent to the condition that the induced subgraph of $G$ induced by $C$ is a complete graph. In some cases, the term clique may also refer to the subgraph directly.

A maximal clique is a clique that cannot be extended by including one more adjacent vertex, that is, a clique which does not exist exclusively within the vertex set of a larger clique. Some authors define cliques in a way that requires them to be maximal, and use other terminology for complete subgraphs that are not maximal.

A maximum clique of a graph, $G$, is a clique, such that there is no clique with more vertices. Moreover, the clique number $ω(G)$ of a graph $G$ is the number of vertices in a maximum clique in $G$.

The intersection number of $G$ is the smallest number of cliques that together cover all edges of $G$.

The clique cover number of a graph $G$ is the smallest number of cliques of $G$ whose union covers the set of vertices $V$ of the graph.

A maximum clique transversal of a graph is a subset of vertices with the property that each maximum clique of the graph contains at least one vertex in the subset.

The opposite of a clique is an independent set, in the sense that every clique corresponds to an independent set in the complement graph. The clique cover problem concerns finding as few cliques as possible that include every vertex in the graph.

A related concept is a biclique, a complete bipartite subgraph. The bipartite dimension of a graph is the minimum number of bicliques needed to cover all the edges of the graph.

Mathematics
Mathematical results concerning cliques include the following.
 * Turán's theorem gives a lower bound on the size of a clique in dense graphs. If a graph has sufficiently many edges, it must contain a large clique. For instance, every graph with $$n$$ vertices and more than $$\scriptstyle \left\lfloor\frac{n}{2}\right\rfloor \cdot \left\lceil\frac{n}{2}\right\rceil$$ edges must contain a three-vertex clique.
 * Ramsey's theorem states that every graph or its complement graph contains a clique with at least a logarithmic number of vertices.
 * According to a result of, a graph with 3n vertices can have at most 3n maximal cliques. The graphs meeting this bound are the Moon–Moser graphs K3,3,..., a special case of the Turán graphs arising as the extremal cases in Turán's theorem.
 * Hadwiger's conjecture, still unproven, relates the size of the largest clique minor in a graph (its Hadwiger number) to its chromatic number.
 * The Erdős–Faber–Lovász conjecture relates graph coloring to cliques.
 * The Erdős–Hajnal conjecture states that families of graphs defined by forbidden graph characterization have either large cliques or large cocliques.

Several important classes of graphs may be defined or characterized by their cliques:
 * A cluster graph is a graph whose connected components are cliques.
 * A block graph is a graph whose biconnected components are cliques.
 * A chordal graph is a graph whose vertices can be ordered into a perfect elimination ordering, an ordering such that the neighbors of each vertex v that come later than v in the ordering form a clique.
 * A cograph is a graph all of whose induced subgraphs have the property that any maximal clique intersects any maximal independent set in a single vertex.
 * An interval graph is a graph whose maximal cliques can be ordered in such a way that, for each vertex v, the cliques containing v are consecutive in the ordering.
 * A line graph is a graph whose edges can be covered by edge-disjoint cliques in such a way that each vertex belongs to exactly two of the cliques in the cover.
 * A perfect graph is a graph in which the clique number equals the chromatic number in every induced subgraph.
 * A split graph is a graph in which some clique contains at least one endpoint of every edge.
 * A triangle-free graph is a graph that has no cliques other than its vertices and edges.

Additionally, many other mathematical constructions involve cliques in graphs. Among them,
 * The clique complex of a graph G is an abstract simplicial complex X(G) with a simplex for every clique in G
 * A simplex graph is an undirected graph κ(G) with a vertex for every clique in a graph G and an edge connecting two cliques that differ by a single vertex. It is an example of median graph, and is associated with a median algebra on the cliques of a graph: the median m(A,B,C) of three cliques A, B, and C is the clique whose vertices belong to at least two of the cliques A, B, and C.
 * The clique-sum is a method for combining two graphs by merging them along a shared clique.
 * Clique-width is a notion of the complexity of a graph in terms of the minimum number of distinct vertex labels needed to build up the graph from disjoint unions, relabeling operations, and operations that connect all pairs of vertices with given labels. The graphs with clique-width one are exactly the disjoint unions of cliques.
 * The intersection number of a graph is the minimum number of cliques needed to cover all the graph's edges.
 * The clique graph of a graph is the intersection graph of its maximal cliques.

Closely related concepts to complete subgraphs are subdivisions of complete graphs and complete graph minors. In particular, Kuratowski's theorem and Wagner's theorem characterize planar graphs by forbidden complete and complete bipartite subdivisions and minors, respectively.

Computer science
In computer science, the clique problem is the computational problem of finding a maximum clique, or all cliques, in a given graph. It is NP-complete, one of Karp's 21 NP-complete problems. It is also fixed-parameter intractable, and hard to approximate. Nevertheless, many algorithms for computing cliques have been developed, either running in exponential time (such as the Bron–Kerbosch algorithm) or specialized to graph families such as planar graphs or perfect graphs for which the problem can be solved in polynomial time.

Applications
The word "clique", in its graph-theoretic usage, arose from the work of, who used complete subgraphs to model cliques (groups of people who all know each other) in social networks. The same definition was used by in an article using less technical terms. Both works deal with uncovering cliques in a social network using matrices. For continued efforts to model social cliques graph-theoretically, see e.g., , and.

Many different problems from bioinformatics have been modeled using cliques. For instance, model the problem of clustering gene expression data as one of finding the minimum number of changes needed to transform a graph describing the data into a graph formed as the disjoint union of cliques;  discuss a similar biclustering problem for expression data in which the clusters are required to be cliques. uses cliques to model ecological niches in food webs. describe the problem of inferring evolutionary trees as one of finding maximum cliques in a graph that has as its vertices characteristics of the species, where two vertices share an edge if there exists a perfect phylogeny combining those two characters. model protein structure prediction as a problem of finding cliques in a graph whose vertices represent positions of subunits of the protein. And by searching for cliques in a protein–protein interaction network, found clusters of proteins that interact closely with each other and have few interactions with proteins outside the cluster. Power graph analysis is a method for simplifying complex biological networks by finding cliques and related structures in these networks.

In electrical engineering, uses cliques to analyze communications networks, and  use them to design efficient circuits for computing partially specified Boolean functions. Cliques have also been used in automatic test pattern generation: a large clique in an incompatibility graph of possible faults provides a lower bound on the size of a test set. describe an application of cliques in finding a hierarchical partition of an electronic circuit into smaller subunits.

In chemistry, use cliques to describe chemicals in a chemical database that have a high degree of similarity with a target structure. use cliques to model the positions in which two chemicals will bind to each other.

title: Clique (graph theory)


text:
Adrien de Gerlache

Baron Adrien Victor Joseph de Gerlache de Gomery (2 August 1866 – 4 December 1934) was a Belgian officer in the Belgian Royal Navy who led the Belgian Antarctic Expedition of 1897–99.

Early years
Born in Hasselt in eastern Belgium as the son of an army officer, de Gerlache was educated in Brussels. From a young age he was deeply attracted by the sea, and made three voyages in 1883 and 1884 to the United States as a cabin boy on an ocean liner. He studied engineering at the Free University of Brussels. After finishing his third year in 1885, he quit the university and joined the Belgian Navy on 19 January 1886. After graduating from the nautical college of Ostend he worked on fishery protection vessels as second and third lieutenant. In October 1887 he signed on as seaman on the Craigie Burn, an English ship, for a voyage to San Francisco, but the ship failed to round Cape Horn and was sold for scrap in Montevideo. He returned to Europe after spending time in Uruguay and Argentina. After a trip to Constantinople and the Black Sea he worked for the Holland-America Line as fourth officer, before obtaining an appointment as lieutenant in the Belgian Navy. Until July 1894 he was an officer on Ostend-Dover ferries, meanwhile taking courses and becoming a captain on 22 August 1894.

Frustrated by the monotonous work aboard the Ostend-Dover ferries, de Gerlache offered his services to Belgian King Leopold II and Welsh-American adventurer Henry Morton Stanley, for an expedition to the Congo, but the offer was turned down. A letter to polar explorer Otto Nordenskiöld went unanswered. Finally he started planning and promoting his own Antarctic expedition, proposing his plan in 1894 to the Belgian Royal Geographical Society.

First expedition
In 1896, de Gerlache purchased the Norwegian-built whaling ship Patria, which he extensively refitted and renamed Belgica. With a multinational crew including Roald Amundsen, Frederick Cook, Antoni Bolesław Dobrowolski, Henryk Arctowski and Emil Racoviță, he set sail from Antwerp on 16 August 1897.

The Belgica reached the coast of Graham Land on the Antarctic Peninsula in January 1898. Sailing between the Graham Land coast and a string of islands to the west, de Gerlache named the passage Belgica Strait. This strait was later renamed Gerlache Strait in his honour. After charting and naming several islands during some 20 separate landings, they crossed the Antarctic Circle on 15 February 1898.

On 28 February 1898, de Gerlache's expedition became trapped in the ice of the Bellinghausen Sea, near Peter I Island. Despite their efforts, they quickly realised that they would be forced to spend the winter on Antarctica. Total darkness set in on 17 May, lasting until 23 July. Another seven months of hardship followed as the crew laboured to free the vessel from the ice. Several men lost their sanity, including one Belgian sailor who left the ship "announcing he was going back to Belgium". The party also suffered from scurvy.

On 15 February 1899 the vessel was able to begin moving through the channel that the crew had cleared. It took them nearly a month to cover 7 miles, and on 14 March they cleared the ice. The expedition returned to Antwerp on 5 November 1899. In 1902, de Gerlache's book Quinze Mois dans l'Antarctique ('Fifteen Months in Antarctica'), published in 1901, was awarded a prize by the Académie française.

The fungi collected during the expedition were described in a paper published in 1905 by Marietta Hanson Rousseau and Elisa Caroline Bommer.

Later years
de Gerlache participated in several other expeditions, including:
 * a commercial and scientific expedition to the Persian Gulf in 1901
 * the first Antarctic expedition (1903-1905) of Jean-Baptiste Charcot. de Gerlache began on this voyage but returned to Belgium when the ship reached Madeira
 * expedition to the Greenland Sea on board the Belgica (1905)
 * expedition to the Barents Sea and Kara Sea (1907)
 * expedition to Greenland, Spitsbergen and the Franz Jozef archipelago on board the Belgica (1909)

He had two children with his first wife, Suzanne Poulet, whom he married in 1904: Philippe (born 1906) and Marie-Louise (born 1908). After this marriage ended in 1913, de Gerlache married Elisabeth Höjer from Sweden. With her, he had another son, the explorer Gaston de Gerlache in 1919. In the 1950s, Gaston followed in his father's footsteps, participating in a Belgian research station in Antarctica.

Adrien de Gerlache died in Brussels in 1934, aged 68, from paratyphoid fever.

Tributes
Several geographical features were named in his honour, mostly in Antarctica: Cape Gerlache, Mount Gerlache, Gerlache Inlet, Gerlache Island, Gerlache Strait and the de Gerlache seamounts, as well as Pic de Gerlache in Greenland and de Gerlache crater, near the lunar south pole. One of Antwerp's quays is named De Gerlachekaai.

title: Adrien de Gerlache