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Severe thunderstorm warning

A severe thunderstorm warning (SAME code: SVR) is a type of public warning for severe weather that is issued by weather forecasting agencies worldwide when one or more severe thunderstorms have been detected by Doppler weather radar, observed by weather spotters, or reported by an emergency management agency, law enforcement, or the general public. Unlike a watch, a warning is issued to areas in the direct path of active severe thunderstorms, that are expecting a direct impact typically within an hour. Severe thunderstorms can cause property damage and injury due to large hail, high winds, and flooding due to torrential rainfall. The exact criteria to issue a warning varies from country to country.

In the United States, the National Weather Service issues a warning when an observed thunderstorm is producing wind gusts of at least 58 mph, or hail of at least 1 in in diameter. Most forecasting agencies have similar criteria, but some agencies, such as Environment Canada, also include high rainfall rate. Others may instead issue a flood advisory or in the case of the National Weather Service, a flash flood warning.

Definition
A severe thunderstorm warning indicates the warned area is in impending danger from hail or wind speeds meeting warning criteria as well as from lightning and hydrological impacts associated with the storm cell. Severe thunderstorms can and occasionally do produce tornadoes without warning. While not all severe thunderstorms produce tornadoes, they can produce serious straight line wind damage as severe as a lower-category tornado or hurricane, and can actually cover a much wider area than that exceeded by a tornado's comparatively narrow path width.

If a tornado is detected on radar or is sighted visually, a tornado warning will be issued either in replacement of or concurrently to the existing severe thunderstorm warning. Generally, but not always, a severe thunderstorm watch or tornado watch (or a regional equivalent thereof) will precede a warning. If a tornado warning is issued, based on Doppler weather radar, it means strong rotation has been detected within a thunderstorm. Usually, if a thunderstorm is producing only weak rotation, it will only yield hazardous weather warranting a severe thunderstorm warning. However, the public will usually be advised this type of rotation has been detected and that the storm in question should be watched closely in the near future for further intensification.

United States
In the United States, the National Weather Service (NWS) defines a severe thunderstorm as having large hail of 1 in in diameter or larger, surface wind speeds of 58 mph or greater, and/or a tornado. Prior to January 2010, the hail size for which a thunderstorm would be considered severe was 0.75 in; public complacency due to overly frequent issuances of severe thunderstorm warnings and recent studies stating hail did not produce significant damage on the ground until it reached one inch in diameter caused the upgrade in hail criteria. Severe thunderstorm warnings are issued by the National Weather Service through the agency's local Weather Forecast Offices, which utilize WarnGen software integrated into the Advance Weather Interactive Processing System (AWIPS) to generate the warning statement; it is then disseminated through various communication routes accessed by the media and various agencies, on the internet, to NOAA satellites, over NOAA Weather Radio and, depending on the storm's severity and at the office's discretion, via activation of the Emergency Alert System to local broadcast media and Wireless Emergency Alerts for cellular phones.

Local NWS forecast offices outline warnings for tornadoes and severe thunderstorms in polygonal shapes for map-based weather hazard products distributed to the main agency, individual forecast office websites and the Storm Prediction Center (including open-source APIs available for free use to public weather websites and mobile apps), based on the storm's projected path as determined by Doppler weather radar at the time of the warning's issuance. In NWS text products, warnings are usually illustrated by individual counties, parishes or other county-equivalent jurisdictions (sections or the entirety thereof, and in list format if it covers more than one jurisdiction), particularly dependent on the jurisdiction's total land area. Prior to October 2007, warnings were issued by the National Weather Service on a per-county basis. SPC and NWS products, as well as severe weather alert displays used by some television stations, typically highlight severe thunderstorm warnings with a yellow or orange polygon or filled county/parish/equivalent jurisdiction outline.

The NWS has the option of adding enhanced wording to severe thunderstorm warnings and update statements issued as a Severe Weather Statement (SVS)—"particularly dangerous situation" (PDS), "severe thunderstorm emergency", or, as used by some Central and Southern Region offices as indicative PDS wording, "this is a very dangerous storm"—when an extremely intense severe thunderstorm expected to impact a densely populated area contains very large hailstones and/or intense straight-line winds capable of causing major structural damage (especially to roofs, windows, siding and structures of poor construction such as outbuildings and mobile homes), and severe injury if not death to people and animals exposed outdoors (from either repeated hail-induced blunt trauma or wind-generated debris). Although it is an unofficial alert product, a "severe thunderstorm emergency" statement—an extension of the tornado emergency statements issued to warn of a violent tornado impacting populated areas—is the highest and most urgent level relating to non-tornadic severe thunderstorms. When a threat of tornadic activity exists (especially if a tornado watch is in effect), local NWS forecast offices, particularly those in the Great Plains or Southeastern U.S., will sometimes include a safety precaution action statement indicating "Severe thunderstorms can produce tornadoes with no advance warning..." or similar wording in their severe thunderstorm warnings to advise the public to keep abreast of possible tornado development and any tornado warnings that may be issued.

As part of the agency’s March 2012 implementation of a multi-tier Impact Based Warning (IBW) system to notify the public and emergency management officials of the severity of specific severe weather phenomena, National Weather Service-issued severe thunderstorm warnings and associated Severe Weather Statements providing updated storm information include event tags at the bottom of the product text providing summarical estimates of straight-line wind speeds (sustained or gusts) and hail size and, when applicable, an indication of possible tornadic development. The product text will also provide a summary of impacts to life and property that may be caused by the hailstones and winds being produced by the parent thunderstorm. Initially implemented at six NWS offices in Kansas and Missouri, the categorical threat and damage indicator text—which are applicable to all of the agency’s Weather Forecast Offices, primarily those operating within the agency's Central and Southern Region divisions—were expanded to 33 additional Central Region WFOs in March 2013; eight additional offices operating within the Eastern, Southern and Western Region divisions began using the IBW indicators in March 2014. The entire agency began using the format in 2016. The threat indicators consist of three coded taglines, ascending by observational level:
 * Tornado – indicates the mesocyclone of the parent severe thunderstorm is producing circulation at or near the cloud base, which may warrant the issuance of a tornado warning if base-level rotation strengthens. When incorporated into the storm impact summary, the tornado tag (appearing in applicable severe thunderstorm warning products as “TORNADO...POSSIBLE”) will precede the wind and hail tags.
 * Hail – indicates the estimated size of hail (measured in inches) being produced by the parent severe thunderstorm (e.g., “HAIL...1.25IN”). When included, the “Impact” section of the warning text will describe potential damage impacts from the hailstones, with the impact message varying in severity depending on radar estimated or observed reports of measured large hail (e.g., “Hail damage to vehicles is expected.”) and the “Hazard” section will provide a comparison of the size of hailstones to objects of similar size (e.g., “baseball size hail” for hailstones measuring 2.75"). (If the tag lists either “HAIL...0.00IN”, indicating no hail is accompanying the storm, or “HAIL...<.75IN”, indicating hailstones below severe criteria that may range in equivalent size from peas [.25"] to pennies [.75"], no hail size will be indicated in the “Hazard” row nor will a description of damage risk be included in the “Impact” section.)
 * Wind – indicates estimated speed (in miles per hour) of wind gusts produced by the parent thunderstorm (e.g., “WIND...70MPH”). When included, the “Impact” section of the warning text will describe potential damage impacts from the straight-line winds, varying in severity depending on wind strength (e.g., “Expect considerable tree damage. Wind damage is also likely to mobile homes, roofs, and outbuildings.”).

Since July 28, 2021 (or as late as August 2 in certain County Warning Areas), the NWS has incorporated categorical damage threat indicators for higher-end hail and/or wind events at the bottom of text products for severe thunderstorm warnings (including update statements to existing warnings issued as Severe Weather Statements): Similar to the indicators used for tornado warnings since the 2013 implementation of its Impact Based Warning system, the categorical criteria—which will be applicable to all NWS Weather Forecast Offices—was introduced to further explain to the public of the dangers of some thunderstorms, especially those that occur in the Great Plains, that can produce massive hailstones of baseball size (2.75 in) or larger that may fall fast enough to severely injure if not kill a person by repeated blunt trauma, and winds that can cause damage equivalent to hurricanes and tornadoes (especially to roofs and weaker structures such as outbuildings and mobile homes). When deemed necessary, initial warnings and Severe Weather Statement updates containing the "destructive" tag will be disseminated into the Wireless Emergency Alerts system as well.
 * Considerable – to be used when hail of 1.75 in or larger and/or winds at or above 70 mph is indicated by radar or observed.
 * Destructive – to be used when hail of 2.75 in or larger and/or winds at or above 80 mph is indicated by radar or observed. (Warnings assigned this indicator incorporate the notation "THIS IS A DESTRUCTIVE STORM FOR[...]"—which superseded the boilerplate "this is a particularly dangerous situation" wording—between the storm summary and hazard information in the product text to indicate certain areas under greatest threat from the specified wind speeds and/or hail size.)

Canada
In Canada, a severe thunderstorm is defined as having wind gusts of greater than 90 kph, hail with a diameter of greater than 2 cm, rainfall rates of greater than 50 mm in one hour or greater than 75 mm in three hours, or tornadoes. Environment and Climate Change Canada issues severe thunderstorm warnings through regional offices of the Meteorological Service of Canada based in Vancouver, Edmonton, Winnipeg, Toronto, Montreal and Dartmouth for specified municipalities and census subdivisions, sometimes including areas adjacent to a particular warned thunderstorm that are not in the immediate approximate path but may experience severe weather from adjacent thunderstorms during the warning timeframe. Warnings are disseminated to the public through broadcast and online media outlets, and Weatheradio Canada; depending on storm severity and regional office discretion, the warning may require activation of the National Public Alerting System (Alert Ready) (Système national d'alertes à la population [En Alerte]) and feeding provincial alerting systems (such as Alberta Emergency Alert and SaskAlert) to distribute the alert to local broadcast media and cellular phones.

United Kingdom
In United Kingdom, a severe thunderstorm is defined as having hail in excess of 2 cm and straight-line winds in excess of 89 kph. The Met Office issues de facto severe thunderstorm warnings through general-purpose weather warning products disseminated by the National Severe Weather Warning Service (classified as yellow, amber or red, depending on storm severity and proximity to the time of expected onset of storm impacts).

Australia
In Australia, a severe thunderstorm is defined as having damaging winds in excess of 90 kph, large hail of 2 cm or larger, heavy rainfall, and flash flooding. Severe thunderstorm warnings are issued by regional offices of the Bureau of Meteorology (BOM) based in Melbourne Docklands, Adelaide, Darwin, Perth and Brisbane. BOM-issued severe thunderstorm warnings are outlined as either a broad-based warning, covering expected impacts within a weather reporting area, or as a detailed warning, when a thunderstorm is within weather-watch radar range and includes a map depicting any existing thunderstorms and the forecast direction of movement for up to 60 minutes.

New Zealand
In New Zealand, a severe thunderstorm is defined by the Meteorological Service of New Zealand (MetService) (Te Ratonga Tirorangi) as having large hail of 20 mm, damaging winds of 110 km/h, rainfall rates of at least 25 mm per hour and/or tornadoes producing winds above 116 km/h (rated F1 or stronger on the Fujita Scale). MetService issues severe thunderstorm warnings to alert regions expected to experience severe weather phenomena meeting regional criteria and utilize the Common Alerting Protocol (CAP) to generate the warning statement. The warning is then disseminated to the public through terrestrial television and radio stations, online media, mobile app and SMS messaging through Emergency Mobile Alert (EMA); if a tornado has been sighted or indicated by radar within the warned area during the severe thunderstorm warning's duration, civil defense sirens, if present, are usually activated within the region to be affected to inform people who are present outdoors of the approaching tornado threat.

Philippines
In the Philippines, a severe thunderstorm is defined by the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) as having strong winds, large hail, torrential rainfall, tornadoes, flash flooding and/or landslides. PAGASA, through its regional services divisions, issue thunderstorm advisories to alert regions and/or provinces expected to experience severe weather phenomena meeting regional criteria within a period of two hours. Warnings are disseminated to the public through terrestrial television and radio outlets, online media, and via SMS messages through the National Disaster Risk Reduction and Management Council's Emergency Cell Broadcast System.

Examples of severe thunderstorm warnings
Here is an example of a Severe Thunderstorm Warning issued by the National Weather Service in San Angelo, Texas. Severe Thunderstorm Warning VAC059-153-600-683-685-140130- /O.NEW.KLWX.SV.W.0529.190814T0058Z-190814T0130Z/ Severe Thunderstorm Warning TXC151-253-042245- /O.NEW.KSJT.SV.W.0017.220404T2223Z-220404T2245Zny

BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service San Angelo TX 523 PM CDT Mon Apr 4 2022

The National Weather Service in San Angelo has issued a

Western Jones County in west central Texas... East central Fisher County in west central Texas...
 * Severe Thunderstorm Warning for...

 * Until 545 PM CDT.

moving east at 40 mph.
 * At 521 PM CDT, a severe thunderstorm was located near Neinda,

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to roofs, siding, and trees.

Neinda around 525 PM CDT. Anson around 540 PM CDT.
 * This severe thunderstorm will be near...

Other locations impacted by this severe thunderstorm include Truby and The Intersection Of Us-180 And Ranch Road 126.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a building.

To report severe weather, contact your nearest law enforcement agency. They will send your report to the National Weather Service office in San Angelo.

Large hail and damaging winds and continuous cloud to ground lightning is occurring with this storm. Move indoors immediately. Lightning is one of nature`s leading killers. Remember, if you can hear thunder, you are close enough to be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3261 10025 3276 10031 3294 9990 3263 9981 TIME...MOT...LOC 2221Z 258DEG 33KT 3271 10012

HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...1.00 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...60 MPH

$$

TP

This is a Severe Thunderstorm Warning issued for a cluster of severe thunderstorms.

Severe Thunderstorm Warning ALC003-FLC033-113-130200- /O.NEW.KMOB.SV.W.0225.200713T0114Z-200713T0200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service Mobile AL 814 PM CDT Sun Jul 12 2020

The National Weather Service in Mobile has issued a

Southeastern Baldwin County in southwestern Alabama... West central Santa Rosa County in northwestern Florida...  Escambia County in northwestern Florida...
 * Severe Thunderstorm Warning for...

 * Until 900 PM CDT.

Bay Minette, moving southeast at 35 mph.
 * At 813 PM CDT, a cluster of severe thunderstorms was located near

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Ensley, Gonzalez, Bay Minette, Pace, Lillian, Molino and Perdido Beach.
 * Locations impacted include...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a building.

Damaging winds and continuous cloud to ground lightning is occurring with this storm. Move indoors immediately. Lightning is one of nature's leading killers. Remember, if you can hear thunder, you are close enough to be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3022 8750 3092 8781 3099 8770 3070 8706 TIME...MOT...LOC 0113Z 301DEG 31KT 3084 8779

HAIL...<.75IN WIND...60MPH

$$

CGAL

This is a Severe Thunderstorm Warning for winds associated with a strong outflow boundary, as opposed to a traditional thunderstorm.

287 WUUS53 KLOT 162204 SVRLOT ILC031-043-063-093-097-111-197-162245- /O.NEW.KLOT.SV.W.0073.240616T2204Z-240616T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service Chicago/Romeoville 504 PM CDT Sun Jun 16 2024

The National Weather Service in Chicago has issued a

Southeastern Kendall County in northeastern Illinois... Lake County in northeastern Illinois...  Will County in northeastern Illinois...  Northeastern Grundy County in northeastern Illinois...  Northeastern McHenry County in northeastern Illinois...  DuPage County in northeastern Illinois...  Cook County in northeastern Illinois...
 * Severe Thunderstorm Warning for...

 * Until 545 PM CDT.

located along a line extending from Channel Lake to Elk Grove Village to near Romeoville to near Morris, moving east at 35 mph.  This strong surge of outflow winds from weakening thunderstorms will produce wind gusts of 50 to locally 60 mph, strong enough to  down some trees and powerlines. These strong winds will be  accompanied by little or no rain.
 * At 502 PM CDT, severe outflow winds from thunderstorms were

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Chicago, Joliet, Waukegan, Arlington Heights, Bolingbrook, Des Plaines, Mount Prospect, Downers Grove, Glenview, and Elmhurst around 510 PM CDT. Skokie, Orland Park, Berwyn, Oak Park, Austin, Highland Park, Wilmette, Zion, Brookfield, and Justice around 515 PM CDT. Cicero, Evanston, Oak Lawn, Irving Park, West Ridge, Burbank, Mokena, Palos Hills, Logan Square, and Humboldt Park around 520 PM  CDT.
 * Severe thunderstorms will be near...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a building.

Wind damage with these storms will occur before any rain or lightning. Do not wait for the sound of thunder before taking cover. SEEK SHELTER IMMEDIATELY inside a sturdy structure and stay away from windows.

&&

LAT...LON 4249 8780 4227 8783 4213 8774 4206 8767 4190 8761 4190 8760 4188 8762 4185 8761     4178 8756 4173 8757 4129 8793 4129 8801      4128 8802 4128 8847 4160 8822 4199 8809      4250 8825 TIME...MOT...LOC 2202Z 258DEG 32KT 4247 8815 4201 8801 4162 8813 4136 8833

HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...<.75 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...60 MPH

$$

Izzi

This is a Severe Thunderstorm Warning with a "considerable" tag to denote that 70 mph wind gusts were possible. � 664 WUUS53 KLBF 052239 SVRLBF NEC017-031-052300- /O.NEW.KLBF.SV.W.0108.210805T2239Z-210805T2300Z/ BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service North Platte NE 539 PM CDT Thu Aug 5 2021 The National Weather Service in North Platte has issued a * Severe Thunderstorm Warning for...  East central Cherry County in north central Nebraska...   Southwestern Brown County in north central Nebraska... * Until 600 PM CDT. * At 539 PM CDT, a severe thunderstorm was located 12 miles southwest of Johnstown, or 18 miles southwest of Ainsworth, moving southeast at 30 mph. HAZARD...70 mph wind gusts and quarter size hail. SOURCE...Radar indicated. IMPACT...Hail damage to vehicles is expected. Expect considerable tree damage. Wind damage is also likely to mobile homes, roofs, and outbuildings. * Locations impacted include... Moon Lake, Willow Lake State Wildlife Management Area and Long Lake State Wildlife Management Area. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. && LAT...LON 4244 10033 4249 10019 4227 9991 4219 10022 TIME...MOT...LOC 2239Z 327DEG 26KT 4242 10018 THUNDERSTORM DAMAGE THREAT...CONSIDERABLE HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...1.00 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...70 MPH $$ Sporer

This is a Severe Thunderstorm Warning with "destructive" wording to denote that three-inch hail was possible with this storm, with a request for activation of Wireless Emergency Alerts (as indicated by the wording "BULLETIN - EAS ACTIVATION REQUESTED" at the top of the warning). � 115 WUUS53 KLBF 052249 SVRLBF NEC089-149-052330- /O.NEW.KLBF.SV.W.0109.210805T2249Z-210805T2330Z/ BULLETIN - EAS ACTIVATION REQUESTED Severe Thunderstorm Warning National Weather Service North Platte NE 549 PM CDT Thu Aug 5 2021 The National Weather Service in North Platte has issued a * Severe Thunderstorm Warning for...  Northeastern Rock County in north central Nebraska...   Southwestern Holt County in north central Nebraska... * Until 630 PM CDT. * At 548 PM CDT, a severe thunderstorm was located near Newport, or  15 miles east of Bassett, moving southeast at 40 mph. THIS IS A DESTRUCTIVE STORM APPROACHING STUART! HAZARD...Three inch hail and 70 mph wind gusts. SOURCE...Radar indicated. IMPACT...People and animals outdoors will be severely injured. Expect shattered windows, extensive damage to roofs, siding, and vehicles. * Locations impacted include...  O'neill, O'Neill, Atkinson, Stuart, Newport and Emmet. This includes the following highways... Highway 20 between mile markers 265 and 308. Highway 281 between mile markers 183 and 189. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. Prepare immediately for large hail and damaging winds. People outside should move immediately to shelter inside a strong building. Stay away from windows. This is a dangerous storm. Prepare immediately for large destructive hail capable of producing significant damage. People outside should move to shelter inside a strong building, and stay away from windows. && LAT...LON 4256 9946 4274 9928 4252 9857 4224 9884 TIME...MOT...LOC 2248Z 300DEG 33KT 4262 9924 THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...3.00 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...70 MPH $$ Sporer On August 16, 2019 at 1:31 a.m. MDT, the National Weather Service in Cheyenne, Wyoming incorporated the "emergency" wording into a Severe Thunderstorm Warning. In this instance, the "severe thunderstorm emergency" statement was included to denote that 3 in diameter hail (as confirmed by storm spotter reports) was imminent in portions of Scotts Bluff, Banner and Sioux Counties in Nebraska, specifically areas around the towns of Scottsbluff and Gering.

� 187 WWUS55 KCYS 160731 SVSCYS

Severe Weather Statement National Weather Service Cheyenne WY 131 AM MDT Fri Aug 16 2019

NEC007-157-165-160815- /O.CON.KCYS.SV.W.0342.000000T0000Z-190816T0815Z/ Scotts Bluff NE-Banner NE-Sioux NE- 131 AM MDT Fri Aug 16 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 215 AM MDT FOR SCOTTS BLUFF...NORTHEASTERN BANNER AND SOUTHEASTERN SIOUX COUNTIES...

...THIS IS A SEVERE THUNDERSTORM EMERGENCY FOR SCOTTSBLUFF AND GERING!...

At 129 AM MDT, a severe thunderstorm was located near Scotts Bluff National Monument, or near Scottsbluff, moving east at 40 mph. 3 INCH DIAMETER HAIL IS IMMINENT! PREPARE NOW FOR DESTRUCTIVE HAIL!

This is a very dangerous storm!

HAZARD...Three inch hail and 60 mph wind gusts.

SOURCE...Trained weather spotters.

IMPACT...People and animals outdoors will be severely injured. Expect shattered windows, extensive damage to roofs, siding, and vehicles.

Locations impacted include... Scottsbluff, Gering, Mitchell, Terrytown, Minatare, Wildcat Hills State Recreation Area, Lake Minatare Campground, Wildcat Hills Campground, Scotts Bluff National Monument, Hubbard Hill, Scottsbluff Airport, Lake Minatare, Lake Alice, Melbeta and McGrew.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a building.

This is a dangerous storm. Prepare immediately for large destructive hail capable of producing significant damage. People outside should move to a shelter, inside a strong building and away from windows.

&&

LAT...LON 4185 10394 4233 10379 4230 10344 4209 10345 4209 10340 4200 10340 4198 10336 4156 10337     4170 10388 TIME...MOT...LOC 0729Z 288DEG 34KT 4189 10374

HAIL...3.00IN WIND...60MPH $$

Lyons

title: Severe thunderstorm warning


text:
User talk:Michaelg2co

7/23/03 -- I'm a newcomer to this wiki. When I looked up "Earth Science" in the directory, I noted that there are more than a few stub pages and links to pages that don't exist yet. I hope to remedy that situation by my own efforts and those of you who lurk and/or contribute to this page. Please contribute or correct as you see fit.

I'd also like to hear from any of you out there. My personal e-mail address is michaelg2@mindspring.com. I also run a website, Websurfers Biweekly Earth Science Review (www.mindspring.com/michaelg2/index.html); it's basically a jumpsite with a growing amount of original intellectual content.

CV: 20+ years with U.S. Dept. of Interior (USGS, BLM); six years with Denver Museum of Natural History; three years with Morrison Natural History Museum. Professional emphasis: field geology, paleontology, technical editing and publishing, and information technology in the sciences. Personal interests: SCUBA and free diving, and travel to/living in WARM countries surrounded by salt water.

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

title: User talk:Michaelg2co


text:
Talk:Colon classification

Untitled
can we have some examples, please?

Colon Classification and faceted classifications
''Discussion moved from user talk pages. It should continue here.''

I'm sorry I had to remove your Yahoo! example from Colon Classification. CC isn't a general term for faceted classifications and the use of colons or whatever punctuation doesn't make any classification a faceted one. The page probably isn't at its current state clear enough about this. Yahoo! directory seems to use a normal hierarchical classification, but I'm not completely sure. Do you know if it is a real faceted classification? Wipe 07:01, 24 May 2005 (UTC)

 * For Wipe: You expressed some doubt as to whether Yahoo! is an example of Colon Classification. While it is debatable, there are some people that do make this claim. I remember this article from graduate school and thought it is both a good example of Colon Classification that people reading the Wikipedia would understand - unlike the example in Wikipedia from the same article.

 * My recollection of all the details of Colon Classification is a little bit hazy - so it isn't an issue for me one way or another. Scott Jenkins 13:27, 24 May 2005 (UTC)

No, Yahoo! is not an example of Colon Classification, as you'll probably notice if you read that article you cited thoroughly. The author tries to find similarities between Yahoo!'s classification scheme and Ranganathan's Colon Classification, which is a complex and well defined system with specific rules. Colon Classification is a faceted classification scheme, but there are others. Nothing convinces me that Yahoo! uses one. Indeed, the author of the article somewhat fails in her attempt to show the similarities.

"Once at 'Education: Higher Education: Colleges and Universities' the next link for the geographic subcategory ('United States@') actually drops me back into the Regional hierarchy, as noted initially."

That's not proper faceted classification! The article she's seeking is only in one place (or class). Most likely the hierarchy tree of classes repeats certain "facets" in its structure, such as a class named "Colleges and Universities" under every single "Education" class under each "Cities" class. A faceted classification on the other hand would give each article a description of it's own based on some predetermined aspects (facets) such as place, time, and nature. The information seeker would not have to jump from class to class when browsing the directory. They would just give a value to as many facets as necessary and they would be presented with a list of search results matching the selections made. Wipe 15:57, 24 May 2005 (UTC)

 * We agree that Yahoo! is not Colon Classification. Where we disagree is on two points: 1. Whether Yahoo! uses faceted classification and 2. whether it is in some ways derived from Colon Classification.

 * The author of the article linked above suggests that the directory serves as a faceted structure. I think Yahoo!'s has little in the way of formal structure. However, I do think there is an informal structure of facets that enable users to keyword search them across the directory. Example: search 'organization' and take a look at the different directory links. Organization is essentially a conceptual facet that crosses the heirarchial structure of Yahoo! and it can be searched. A casual search across other categories will reveal others. This fact did not occur by accident. So, we have some evidence for faceted classification in Yahoo!

 * You also seem to be approaching this more from a document perspective. While Yahoo! is clearly limiting the number of specific facets assigned to a particular site to one (or in some cases a few), this is more a function of the informal nature of their system and the issue of redundancy that too many facets would introduce. If you approach it from a document perspective, then it is harder to see the facets in Yahoo! - which I think is one of the issues you are raising.

 * Now the next question is about whether it is derivative. At its simpliest, you could argue that idea of facets are derived from Colon Classification so that if this is an application then it has relevant. However, I think someone wanting to bring the similarities and differencies and the impact of CC on Yahoo! and similiar sites into sharp relief could do so - and in doing so clearly convey what Colon Clasification is and is not. Part of my including it was to see if someone would do this - rather than simply deleting the issue because it was easier to do or because in the short term it might cause some confusion.

 * I think having a concrete example that people reading the article would be familiar with (and let's face it, no one outside of Indian libraries or those with an interest in classification attending a library school is going to know anything about Colon Classification) would help people get a better understanding of it and its significance. I'm not the person to write that article - but, it seems like it is worth doing. This also seems to be interest in having examples as is indicated by the comment above - can we have some examples, please? --Scott Jenkins 17:53, 24 May 2005 (UTC)

 * I have added the *only* example that I have found anywhere on the internet and have found only 3 books that even touch on CC. One of them is a book on how to classify a book using CC referenced another book which gives a much more detailed view of the layout of CC. I would greatly appreciate if someone out there who knows how to obtain this kind of information to add the grammars to each general subject or leave a note on my talk page. Merosonox 07:23, 26 September 2006 (UTC)

A common english word such as organization is surely going to appear more than once in any large general directory or catalogue. Moreover, facet doesn't mean a single concept under which documents (or subclasses) can be classified. It's a general aspect or attribute that can be applied to all entities in some group. The possible values of these attributes are specified so that we have a real documentation language and not just a collection of arbitrary keywords. For example, had we a list of organizations we might select purpose as one of the facets. One allowed value would be education. It's not useful to claim that anything that has keywords or subject headings is faceted (as if the concept of keyword would be a single all-encompassing facet). The Yahoo! directory classification is much like any normal enumerated library classification, isn't it? All it lacks is the shorthand representation in numbers.

You make good points on developing the article. I may try to improve it although I'm not an expert. I agree that reverting additions made in good faith is not nice. Luckily, discussing controvensial edits and issues on article talk pages is always possible and in fact an essential part of the development of the encyclopedia. The removed stuff can also be retrieved from page history.

As for this CC article, it shouldn't really contain much information on facet analysis and faceted classifications in general, or their relationship with other schemes (except for CC). It should concentrate on the special features of CC and leave the other stuff for the article Faceted classification. Wipe 23:06, 24 May 2005 (UTC)

 * I agree that organization would appear quite a bit as a keyword. However, if you do a search on two words with essentially the same meaning in Yahoo!'s directory - association (509) and organization (2,102). You can even find examples where one is subhumed under the other - Education Organizations > Trade Associations. This may also match your example of a purpose facet; again, I'm not sure.

 * I think this example demonstrates that there is more going on here then merely arbitrary keywords and that I think it at least raises the question whether there is something like facet analysis going on behind the scenes. And your comment about Yahoo! classification being much like normal enumerated library classification is why it might be a good example to use to illustrate the significance of Colon Classiciation. I think your main point is that it is too far of a stretch for this article - which it may very well be.

 * However, I wish we could think of a popular example (if not Yahoo!) that was in some way derivative that could illustrate facet analysis and those things that are unique to Colon Classification that would be useful aid to the understanding of the reader of the Colon Classification article. It has been a few years since I looked into Colon Classification, so I am not sure I have a good enough understanding to identify this kind of example (my selection of Yahoo! might even be the proof of not having this understanding!). --Scott Jenkins 23:10, 25 May 2005 (UTC)

 * I'm not very familiar with this system, but would "tagging" based systems like del.icio.us qualify? What they seem to have in common is that items can be classified as a combination of keywords. Kith 01:29, 1 November 2006 (UTC)

Poor article quality
This article provides sources at the bottom, but citations are not used anywhere.

Also, from: Universal Decimal Classification

"... at the end of the 19th century ... the UDC was developed as a new analytico-synthetic classification system..."

This really contradicts the first two sentences in this article:

"Colon classification (CC) ... was the first ever faceted (or analytico-synthetic) classification. The first edition was published in 1933."

title: Talk:Colon classification


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Deconvolution

In mathematics, deconvolution is the inverse of convolution. Both operations are used in signal processing and image processing. For example, it may be possible to recover the original signal after a filter (convolution) by using a deconvolution method with a certain degree of accuracy. Due to the measurement error of the recorded signal or image, it can be demonstrated that the worse the signal-to-noise ratio (SNR), the worse the reversing of a filter will be; hence, inverting a filter is not always a good solution as the error amplifies. Deconvolution offers a solution to this problem.

The foundations for deconvolution and time-series analysis were largely laid by Norbert Wiener of the Massachusetts Institute of Technology in his book Extrapolation, Interpolation, and Smoothing of Stationary Time Series (1949). The book was based on work Wiener had done during World War II but that had been classified at the time. Some of the early attempts to apply these theories were in the fields of weather forecasting and economics.

Description
In general, the objective of deconvolution is to find the solution f of a convolution equation of the form:

 * $$f * g = h \, $$

Usually, h is some recorded signal, and f is some signal that we wish to recover, but has been convolved with a filter or distortion function g, before we recorded it. Usually, h is a distorted version of f and the shape of f can't be easily recognized by the eye or simpler time-domain operations. The function g represents the impulse response of an instrument or a driving force that was applied to a physical system. If we know g, or at least know the form of g, then we can perform deterministic deconvolution. However, if we do not know g in advance, then we need to estimate it. This can be done using methods of statistical estimation or building the physical principles of the underlying system, such as the electrical circuit equations or diffusion equations.

There are several deconvolution techniques, depending on the choice of the measurement error and deconvolution parameters:

Raw deconvolution
When the measurement error is very low (ideal case), deconvolution collapses into a filter reversing. This kind of deconvolution can be performed in the Laplace domain. By computing the Fourier transform of the recorded signal h and the system response function g, you get H and G, with G as the transfer function. Using the Convolution theorem,

 * $$F = H / G \, $$

where F is the estimated Fourier transform of f. Finally, the inverse Fourier transform of the function F is taken to find the estimated deconvolved signal f. Note that G is at the denominator and could amplify elements of the error model if present.

Deconvolution with noise
In physical measurements, the situation is usually closer to

 * $$(f * g) + \varepsilon  = h \, $$

In this case ε is noise that has entered our recorded signal. If a noisy signal or image is assumed to be noiseless, the statistical estimate of g will be incorrect. In turn, the estimate of ƒ will also be incorrect. The lower the signal-to-noise ratio, the worse the estimate of the deconvolved signal will be. That is the reason why inverse filtering the signal (as in the "raw deconvolution" above) is usually not a good solution. However, if at least some knowledge exists of the type of noise in the data (for example, white noise), the estimate of ƒ can be improved through techniques such as Wiener deconvolution.

Seismology
The concept of deconvolution had an early application in reflection seismology. In 1950, Enders Robinson was a graduate student at MIT. He worked with others at MIT, such as Norbert Wiener, Norman Levinson, and economist Paul Samuelson, to develop the "convolutional model" of a reflection seismogram. This model assumes that the recorded seismogram s(t) is the convolution of an Earth-reflectivity function e(t) and a seismic wavelet w(t) from a point source, where t represents recording time. Thus, our convolution equation is

 * $$s(t) = (e * w)(t). \, $$

The seismologist is interested in e, which contains information about the Earth's structure. By the convolution theorem, this equation may be Fourier transformed to

 * $$S(\omega) = E(\omega)W(\omega) \, $$

in the frequency domain, where $$\omega$$ is the frequency variable. By assuming that the reflectivity is white, we can assume that the power spectrum of the reflectivity is constant, and that the power spectrum of the seismogram is the spectrum of the wavelet multiplied by that constant. Thus,

 * $$|S(\omega)| \approx k|W(\omega)|. \, $$

If we assume that the wavelet is minimum phase, we can recover it by calculating the minimum phase equivalent of the power spectrum we just found. The reflectivity may be recovered by designing and applying a Wiener filter that shapes the estimated wavelet to a Dirac delta function (i.e., a spike). The result may be seen as a series of scaled, shifted delta functions (although this is not mathematically rigorous):

 * $$e(t)=\sum_{i=1}^N r_i\delta(t-\tau_i),$$

where N is the number of reflection events, $$r_i$$ are the reflection coefficients, $$t-\tau_i$$ are the reflection times of each event, and $$\delta$$ is the Dirac delta function.

In practice, since we are dealing with noisy, finite bandwidth, finite length, discretely sampled datasets, the above procedure only yields an approximation of the filter required to deconvolve the data. However, by formulating the problem as the solution of a Toeplitz matrix and using Levinson recursion, we can relatively quickly estimate a filter with the smallest mean squared error possible. We can also do deconvolution directly in the frequency domain and get similar results. The technique is closely related to linear prediction.

Optics and other imaging
In optics and imaging, the term "deconvolution" is specifically used to refer to the process of reversing the optical distortion that takes place in an optical microscope, electron microscope, telescope, or other imaging instrument, thus creating clearer images. It is usually done in the digital domain by a software algorithm, as part of a suite of microscope image processing techniques. Deconvolution is also practical to sharpen images that suffer from fast motion or jiggles during capturing. Early Hubble Space Telescope images were distorted by a flawed mirror and were sharpened by deconvolution.

The usual method is to assume that the optical path through the instrument is optically perfect, convolved with a point spread function (PSF), that is, a mathematical function that describes the distortion in terms of the pathway a theoretical point source of light (or other waves) takes through the instrument. Usually, such a point source contributes a small area of fuzziness to the final image. If this function can be determined, it is then a matter of computing its inverse or complementary function, and convolving the acquired image with that. The result is the original, undistorted image.

In practice, finding the true PSF is impossible, and usually an approximation of it is used, theoretically calculated or based on some experimental estimation by using known probes. Real optics may also have different PSFs at different focal and spatial locations, and the PSF may be non-linear. The accuracy of the approximation of the PSF will dictate the final result. Different algorithms can be employed to give better results, at the price of being more computationally intensive. Since the original convolution discards data, some algorithms use additional data acquired at nearby focal points to make up some of the lost information. Regularization in iterative algorithms (as in expectation-maximization algorithms) can be applied to avoid unrealistic solutions.

When the PSF is unknown, it may be possible to deduce it by systematically trying different possible PSFs and assessing whether the image has improved. This procedure is called blind deconvolution. Blind deconvolution is a well-established image restoration technique in astronomy, where the point nature of the objects photographed exposes the PSF thus making it more feasible. It is also used in fluorescence microscopy for image restoration, and in fluorescence spectral imaging for spectral separation of multiple unknown fluorophores. The most common iterative algorithm for the purpose is the Richardson–Lucy deconvolution algorithm; the Wiener deconvolution (and approximations) are the most common non-iterative algorithms. For some specific imaging systems such as laser pulsed terahertz systems, PSF can be modeled mathematically. As a result, as shown in the figure, deconvolution of the modeled PSF and the terahertz image can give a higher resolution representation of the terahertz image.

Radio astronomy
When performing image synthesis in radio interferometry, a specific kind of radio astronomy, one step consists of deconvolving the produced image with the "dirty beam", which is a different name for the point spread function. A commonly used method is the CLEAN algorithm.

Biology, physiology and medical devices
Typical use of deconvolution is in tracer kinetics. For example, when measuring a hormone concentration in the blood, its secretion rate can be estimated by deconvolution. Another example is the estimation of the blood glucose concentration from the measured interstitial glucose, which is a distorted version in time and amplitude of the real blood glucose.

Absorption spectra
Deconvolution has been applied extensively to absorption spectra. The Van Cittert algorithm (article in German) may be used.

Fourier transform aspects
Deconvolution maps to division in the Fourier co-domain. This allows deconvolution to be easily applied with experimental data that are subject to a Fourier transform. An example is NMR spectroscopy where the data are recorded in the time domain, but analyzed in the frequency domain. Division of the time-domain data by an exponential function has the effect of reducing the width of Lorentzian lines in the frequency domain.

title: Deconvolution


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User:Voiceofreason

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title: User:Voiceofreason


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Óðr

In Norse mythology, Óðr (Old Norse for the "Divine Madness, frantic, furious, vehement, eager", as a noun "mind, feeling" and also "song, poetry"; Orchard (1997) gives "the frenzied one" ) or Óð, sometimes anglicized as Odr or Od, is a figure associated with the major goddess Freyja. The Prose Edda and Heimskringla, written in the 13th century by Snorri Sturluson, both describe Óðr as Freyja's husband and father of her daughter Hnoss. Heimskringla adds that the couple produced another daughter, Gersemi. A number of theories have been proposed about Óðr, generally that he is a hypostasis of the deity Odin due to their similarities.

Etymology
The Old Norse theonym Óðr derives from an identical noun, meaning 'mind, wit, soul, sense' but also 'song, poetry', which in turn stems from Proto-Germanic *wōðaz, a substantive of an adjective meaning 'possessed, inspired, delirious, raging'. It is cognate with other nouns from medieval Germanic languages, such as Old English wōð ('sound, noise; voice, song'), Old High German wuot ('thrill, violent agitation') and Middle Dutch woet ('rage, frenzy'). Óðr is also etymologically related to the Old Norse theonym Óðinn, itself deriving from the stem *wōđa- attached to the suffix *-naz ('master of').

Philologist Jan de Vries has argued that the Old Norse deities Óðinn and Óðr were probably originally connected (as in the doublet Ullr–Ullinn), with Óðr (*wōđaz) being the elder form and the ultimate source of the name Óðinn (*wōđa-naz). He further suggested that the god of rage Óðr–Óðinn stood in opposition to the god of glorious majesty Ullr–Ullinn in a similar manner to the Vedic contrast between Varuna and Mitra.

The adjective *wōđaz ultimately stems from a Pre-Germanic form *uoh₂-tós, which is related to the Proto-Celtic terms *wātis, meaning 'seer, sooth-sayer' (cf. Gaulish wāteis, Old Irish fáith 'prophet') and *wātus, meaning 'prophesy, poetic inspiration' (cf. Old Irish fáth 'prophetic wisdom, maxims', Old Welsh guaut 'prophetic verse, panegyric'). According to some scholars, the Latin term vātēs ('prophet, seer') is probably a Celtic loanword from the Gaulish language, making *uoh₂-tós ~ *ueh₂-tus ('god-inspired') a shared religious term common to Germanic and Celtic rather than an inherited word of earlier Proto-Indo-European (PIE) origin. In the case a borrowing scenario is excluded, a PIE etymon *(H)ueh₂-tis ('prophet, seer') can also be posited as the common ancestor of the attested Germanic, Celtic and Latin forms.

Attestations
Óðr is attested in the following sources:

Poetic Edda
Óðr is mentioned in stanza 25 of the Poetic Edda poem Völuspá. The name appears in a kenning for the major goddess Freyja; "Óð's girl" (Old Norse Óðs mey gefna), pointing to a relation with the goddess.

Stanza 47 of the poem Hyndluljóð contains mention of a figure by the name of Œdi. There, Hyndla taunts Freyja, stating that Freyja had run to Œdi, "always full of desire". Scholar Carolyne Larrington says that the identity of Œdi is uncertain; it has been theorized that this may simply be Óðr, or that the figure may be another lover of Freyja's. Scholar John Lindow describes this reference as "puzzling" as no other information is provided regarding the situation referred to by Hyndla. Scholar Britt-Mari Näsström says that this reference likely does not refer to Óðr, rather being the product of the amendments of Sophus Bugge, and that the line simply points to Freyja's lust. Näsström comments that "perhaps the philologists of the nineteenth century were misled by their romantic intentions".

Prose Edda
In chapter 35 of the Prose Edda book Gylfaginning, the enthroned figure of High says that the goddess Freyja "was married to someone named" Óðr. High details that the two produced a daughter, Hnoss, and that this daughter was so fair that the term hnossir (meaning "treasures") derives from her name and is applied to whatever is "beautiful and precious." High adds that Óðr would go off traveling for extended periods, all the while Freyja would stay behind weeping tears of red gold. However, Freyja would travel "among strange peoples" while looking for Óðr, and so had many names. In chapter 36 of Gylfaginning, the stanza of Völuspá mentioning Óðr is quoted.

In chapter 20 of the Prose Edda book Skáldskaparmál, poetic names for the goddess Freyja are listed, including "wife of Óðr". In chapter 36, a prose narrative points out than an excerpt of a work by the skald Einarr Skúlason refers to Freyja as the wife of Óðr ("Óðr's bedfellow"). The same excerpt appears in chapter 49. In chapter 75, Óðr is mentioned a final time in the Prose Edda, where Freyja is cited as having "wept gold" for Óðr.

Heimskringla
In chapter 1 of the Heimskringla book Ynglinga saga, Snorri Sturluson refers to the two in an euhemerized account, stating that Freyja had a husband named Óðr, two daughters named Hnoss and Gersemi, and that they were so beautiful that their names were used for "our most precious possessions" (both of their names literally mean "jewel").

Theories
The name Óðr for Freyja's husband appears prominently in Völuspá 25, where it is said that "Óðs mey" was given to the giants. Nothing else is stated of him by this name in the Eddic poems. In Gylfaginning, Snorri briefly states that Óðr traveled to many nations and that Freyja searched for him in earnest, weeping as she went. Óðr is often theorized as somehow connected to Odin (Old Norse: Óðinn), the head of the Æsir in Norse mythology, by way of etymological similarities between the two names (Lindow states that the linguistic relationship is identical to that of Ullr and Ullin—often considered as variant names of a single god), and the fact that both are described as going on long journeys, though Lindow points out that Snorri is careful to keep them apart. All theories regarding him must remain speculative, due to the limited accounts contained in the sources.

Scholar Viktor Rydberg proposed that Freyja's husband Oðr is identical with the hero Svipdag from the eddic poems Grougaldr and Fjölsvinsmál. Jacob Grimm and others have long identified Menglad ("the neck-lace lover"), Svipdag's love interest in that poem, with Freyja the owner of Brísingamen.

Scholar Hilda Ellis Davidson proposes that a cult of the Vanir may have influenced a cult of the Æsir in the waning days of Norse paganism during the Christianization of Scandinavia, potentially resulting in the figure of Óðr in Norse mythology, which she refers to as a "strange double of Odin".

Scholar Rudolf Simek says that since Óðr appears in a kenning employed by the 11th century skald Einarr Skúlason (in Skáldskaparmál) and in the Poetic Edda poems Völuspá and Hyndluljóð, Óðr is not a late invention. Simek says that "the most obvious explanation is to identify Óðr with Odin," noting the similarity between their names (and agreeing with the Ullr/Ullin parallel), the long absences (comparing them to Odin's exile in Gesta Danorum), and Óðr's marriage with Freyja.

Simek adds that although these similarities exist, there are things that speak against it, such as that "Freyja's tears for Odin and her search are unmotivated," and that "the reference to Hnoss as their only child is surprising - why, for example, should Baldr not be mentioned?" Simek notes that these issues have resulted in sometimes very different explanations; Sophus Bugge and Hjalmar Falk saw a reflection of the Greek god Adonis in Óðr, Rudolf Much saw a reflection in the god Attis, and Lee Hollander theorizes a reflection of the folktale of Amor and Psyche in Snorri's Prose Edda account of Óðr and Freyja.

Simek concurs that, if the two gods were identical, Snorri would not have kept them so apart; yet that the names Odin and Óðr are so close that a lack of connection between the two gods isn't possible. Some scholars have examined the relationship between the two in an attempt to find "older" and "younger" layers in the figures of Óðr and Odin, but Simek says that this approach has yet to yield any results that are convincing due to the sparsity of sources that mention Óðr.

Scholar Stephan Grundy comments that while it is conceivable that Óðr may have been invented as a separate figure from Odin after Christianization, the notion is implausible because a separate, independent figure by the name of Wod survives in folklore involving the Wild Hunt in areas as far south from Scandinavia as Switzerland. Grundy notes that Óðr appears to date to at least before the Viking Age. Grundy opines that "as pointed out by Jan de Vries and others, there is little doubt" that Óðr and Odin were once the same figure. Grundy says that Óðinn is an adjectival form of Óðr, and that Óðr may be the elder form of the two.

Grundy theorizes that the goddesses Frigg and Freyja did not stem from a single goddess. If they did not, Grundy says, the question of explaining the relationship between Freyja and Óðr becomes central, which has been one of the strongest points made in favor of the descent of Frigg and Freyja from a common goddess. Grundy notes that it is rarely mentioned that the Germanic peoples sometimes practiced polygamy, and cites chapter 18 of Tacitus' 1st century AD work Germania, where Tacitus records that while monogamy has very few exceptions in Germanic society, there are those who actively seek a polygamous marriage "for the sake of high birth." Grundy contrasts this with accounts of polygynous marriages among the Merovingians and Carolingians, points out that the only Germanic law-code that expressly forbids such relationships is that of the Visigoths, and notes that while polygynous marriages are rarely attested in Scandinavian sources, Harald I of Norway was married to seven wives simultaneously. Grundy concludes that, as "gods tend to reflect the social norms of their worshippers," it very possible that Odin/Óðr originally "could have rejoiced in Frigg and Freyja simultaneously". Grundy posits that, over time polygynous marriages dwindled during the Viking Age and into the Christianization of the North Germanic territories and, as a result, such a relationship was less easily reflected in the deities of the people.

title: Óðr


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Larry Agran

Lawrence Alan Agran (born February 2, 1945) is an American lawyer and the former mayor and a current city councilmember of Irvine, California.

In May 2023, Agran announced that he would be running as a candidate for the 2024 Irvine mayoral election; if elected, it would be his sixth non-consecutive term as mayor of Irvine.

Early life
Agran was born in Chicago, the son of Selma Elizabeth (Meyerson) and Reuben Agran (originally "Agranowsky"). He was raised in a "politically liberal Jewish household". Agran graduated Phi Beta Kappa from the University of California, Berkeley in 1966 with a Bachelor of Science degree in both history and economics. He then earned a juris doctor (with honors) from Harvard Law School in 1969, specializing in public interest law.

Agran served as legal counsel to the California State Senate Committee on Health and Welfare and taught legislation and public policy at the UCLA School of Law and the University of California, Irvine Graduate School of Management.

Elected service between 1978 and 1990
Between 1978 and 1990, Larry Agran served on the Irvine City Council, including six years as mayor (Irvine employs a council-manager government).

By 1978, Larry Agran had become an active member of various community organizations and was a local attorney. Agran supported increased class integration and the use of federal funding for moderate-income housing in Irvine. Agran's calls for the use of zoning and changes to Irvine's general plan to slow the pace of suburban sprawl and protect open space gained him considerable support from the influential citizen group Irvine Tomorrow, which initiated a door-to-door campaign that helped elect Agran to one of two open seats on the Irvine City Council. Larry Agran won the most votes in his first election for Irvine City Council on March 7, 1978, being elected to his first four-year term in Irvine's City Council.

Larry Agran won the most votes again in the regular municipal election on June 8, 1982, and first served as mayor of Irvine in 1982, continuing through 1984, with a second term starting in 1986. Agran garnered support in the 1986 election by calling for restraints on excessive growth in the city and the preservation of hillsides and farmlands, as well as arguing against new freeways in the Irvine area and advocating for the withdrawal of the city from the Transportation Corridor Agencies. In 1988, Agran won the first-ever direct-election for mayor in Irvine's history. In 1990, Agran was recognized as an elected Democratic Socialists of America "DSAer" by Democratic Left magazine. He lost reelection in the subsequent 1990 mayoral election.

Municipal diplomacy
In 1983, then-Mayor Agran established the Local Elected Officials of America (LEO-USA) project, which founded what became a network of over 250 U.S. local officials advocating for municipal priorities that had an international scope, including the end of the arms race, reduction in U.S. defense spending, and the prioritizing of increased federal spending in economically disadvantaged American cities. Meanwhile, in 1982, the non-profit Center for Innovative Diplomacy (CID) was established in San Francisco by Michael Shuman to advocate for citizen diplomacy and local government action to end the nuclear arms race. The organizations prioritized support for the 1981 Nuclear Weapons Freeze Campaign. Eventually, the organizations aimed at broader diplomatic issues, including sanctuary cities and sister cities in Central America. In the last decade of the Cold War, the networks grew to over 6,000 local officials and activists. CID and LEO-USA merged, under the CID name, and its headquarters moved to Irvine. The merger was followed by the foundation of the Bulletin of Municipal Foreign Policy, a journal that focused on the "municipal foreign policy movement." In 2019, Agran worked with University of California, Irvine doctoral student Ben Leffel to chronicle the role Irvine had to play in establishing CID/LEO-USA its municipal foreign policy network, using original issues of the Bulletin, with articles largely written by the Center's expansive network.

In 1989, Agran implemented the first city-level CFC ban in the country (see below) and is credited with starting "the world’s largest international environmental city government network, ICLEI – Local Governments for Sustainability (formerly, International Council for Local Environmental Initiatives)." In September 2020, Larry Agran was recognized by ICLEI as playing a crucial role in founding the international organization that now includes over 1,750 cities, towns, and counties in 84 countries: "Indeed, the stirrings of a city-led sustainability network can be traced in part to City of Irvine, CA, where, in summer 1989, then-Mayor Larry Agran ushered a first-of-its-kind local ordinance restricting the use of ozone-depleting chlorofluorocarbons (CFCs). Mayor Agran predicted other cities would follow and they did. By July, a two-day conference in Irvine convened 24 U.S. and Canadian cities to explore how local governments could combat the depletion of the ozone layer. They called themselves the North American Congress of Local Governments for a Stratospheric Protection Accord. City of Irvine’s national and global peers transitioned their scope beyond CFCs to consider all environmental pollution the following year during the UN conference mentioned above."

A digital archive was created at the University of California, Irvine of CID's work, as well as the founding of ICLEI.

Human rights ordinance
As Mayor in 1988, Larry Agran led Irvine's City Council to establish the first human rights ordinance of its kind in Orange County, prohibiting discrimination on basis of "race, color, religion, national origin, sex, age, marital status, physical handicap," as well as sexual orientation. The city ordinance was patterned on state and federal law, but went further to protect against discrimination based on sexual orientation. The Irvine City Council voted 4-0 to pass the ordinance.

In 1989, a ballot measure (Measure N), led by Christina Shea and her husband, struck "sexual orientation" as a protected class from the human rights ordinance. In June 2020, the initiative was repealed by a unanimous vote of the Irvine City Council.

Municipal action on chlorofluorocarbons
Agran, Rowland and Molina, championed what was described as one of "the most far reaching measures" in banning commercial process and consumer product use of CFCs. The ordinance is recognized as jumpstarting municipal, state, national, and international efforts to craft legislation that banned CFCs.

Return to city government in 1998
In 1998, Agran re-entered public service as an Irvine City Councillor.

He was again elected mayor in the 2000 election (in which he was unopposed), and in 2002. He later, unsuccessfully, sought the mayoralty in 2012.

Agran rejoined the city council in 2004 and has, for many years, served as a councilor, being most recently re-elected in 2020. He chaired the city's Great Park board until February 2011. (The board is charged with planning, constructing and operating a new park of nearly 1500 acre at the former Marine Corps Air Base El Toro in Irvine.)

Orange County Great Park
As an Irvine City Councilmember, Agran was the chair of the board of directors of the Orange County Great Park project from 2004 to 2010, establishing an international Great Park Master Design Competition that selected landscape architect Ken Smith of New York to create a master design and plan for the 40-year build-out of the Great Park.

Agran supervised removal and clean-up of decades of toxic contamination and building of many of the Great Park's iconic features, including the Great Park Balloon and Carousel, the Palm Court and Arts Complex, the Farm + Food Lab, the South Lawn Soccer Complex, the huge North Lawn (the largest uninterrupted lawn in Southern California), and restoration and repurposing of historic World War II airplane hangars. Under Agran's leadership, the Great Park also began hosting popular events, including Cirque du Soleil, concerts, movies, air shows, regular farmers markets, and countless other community events, boosting attendance at the Great Park to nearly one million annual visitors. Under Agran's tenure, the City of Irvine and the Orange County Great Park also won a national U.S. Department of Energy competition to be the host venue for two U.S. Solar Decathlons, which were ultimately held at the Great Park in 2013 and 2015. Annual financial audits of the Great Park conducted from 2004 through 2010 consistently found that the project was properly managed and that all spending was properly authorized, with no significant irregularities or unaccounted-for funds.

In 2012, the development of the Great Park became politicized. Political opponents of Agran — including newly-elected Mayor Steven Choi and Councilmembers Christina Shea and Jeff Lalloway — won a 3-2 majority on the City Council, and called for another audit of Great Park expenditures. Agran and the other members of the City Council voted for the new audit, specifying that the cost should not exceed $250,000. Councilmembers Christina Shea and Jeff Lalloway were appointed by the city council to a newly constituted City Council Subcommittee charged with overseeing the audit. The committee hired an accounting firm to conduct the audit: Hagen, Streiff, Newton & Oshiro (HSNO).

In January 2014, HSNO issued a preliminary public report declaring that $38 million in Great Park funds were "missing." The funds were, in fact, sitting in a secure state-mandated housing set-aside account.

The budget for the Great Park audit increased from the original $250,000 that had been authorized to $1.7 million to conduct additional investigations into the Great Park.

These expenditures drew the attention of the Joint Legislative Audit Committee of the California State Legislature, which ordered California State Auditor Elaine Howle to conduct a careful review of the entire Great Park audit and the work of the Shea Subcommittee. That review culminated in California State Auditor Report 2015-116, titled "Poor Governance of the $1.7 Million Review of the Orange County Great Park Needlessly Compromised the Review's Credibility." The California State Auditor's report states that the HSNO was hired through a flawed and biased selection process that "cast doubt on the impartiality of Irvine's selection of HSNO as the park review consultant and increased the risk that the city did not select the most qualified vendor to meet its needs." This bidding process all but ensured that HSNO would receive a second, "no-bid" contract. The report is also critical of the Shea Subcommittee's failure to properly oversee the work of the outside firms hired to conduct the audit, noting that the audit itself was driven by political motivations rather than by an objective analysis of the readily-available financial data.

In January 2020, the accounting firm hired by the Shea Subcommittee — Hagen, Streiff, Newton & Oshiro (HSNO) — was ordered to surrender their accountancy license and paid $550,000 in costs and penalties when the California Board of Accountancy said that the firm "failed to comply with professional standards, engaged in numerous acts of negligence, and disseminated false and misleading information" in performing the Great Park audit.

Irvine term limits
In 2014, Irvine voters had approved a rule to its city charter such that councilmembers and the mayors can serve no more than two full 2 year terms for life. Agran championed against the term limits, calling it the "worst written term limits proposal in history" in a statement on the 2014 ballot, saying that it was a bid by then-Mayor Steven Choi to stay in office for eight more years.

Agran is one of the longest serving city council members in Orange County, having served for over three decades on and off the city council since 1978, alongside serving as mayor for five non-consecutive 2 year terms. In December 2022, Agran had resigned with a week left on his term in order to run for another four years on the city council, which prompted his colleague Vice Mayor Tammy Kim to call it a "slippery power grab" and asking Agran if "40 years on the city council [was] not enough".

Orange County Veterans Memorial Park and Cemetery Campaigns
In July 2014, the Irvine City Council unanimously passed Councilmember Larry Agran's motion to transfer 125-acres of city-owned land called the Amended and Restated Development Agreement (ARDA) site to the state for development of a Veterans Memorial Park and Cemetery.

A concept plan for the development was released in June 2016. Estimated cost of the facility was $78 million. In April 2017, the Irvine City Council, on a split 3-2 vote, introduced a land-swap alternative with developer Five Point, trading the park-side ARDA site with a similarly sized location near Interstate 405. In June 2017, with another split 3-2 vote, Irvine City Council directed the City to enter the land swap contract with developer Five Point to move the cemetery.

After the Irvine City Council entered the land swap agreement on October 10, 2017, Irvine residents started a petition referendum campaign to halt the zoning ordinance change that was requisite for the land swap, submitting 19,140 signatures gathered within 30 days, which put the zoning change on the June 2018 ballot. The referendum to halt the zoning change was successful, as measure "B", which would have allowed the relocation of the cemetery, was defeated by 63% to 37%.

In July 2018, the Irvine City Council moved to study a third site for the veterans' cemetery, dubbed the "golf course site". Irvine residents initiated a petition initiative, led by Ed Pope and Larry Agran, to designate by zoning the ARDA site to be the only site in the Great Park area to be used for cemetery purposes. Proponents of the initiative to build at the original ARDA site submitted a reported 19,758 signatures to put the initiative on the November 2020 ballot. In May 2020, Irvine City Council voted 4-1 to adopt the initiative as ordinance, designating the ARDA site as the only site in the Great Park area for cemetery uses.

Presidential candidacy
In 1992, Agran unsuccessfully sought the Democratic Party nomination for president. Agran was generally ignored by the media during his candidacy, a topic heavily covered in the 1995 Brian Springer documentary Spin. The media did not report his polling numbers even as he met or exceeded the support of other candidates such as Jerry Brown. Party officials excluded him from most debates on various grounds, even having him arrested when he interrupted to ask to participate. When he managed to join the other candidates in a forum, his ideas went unreported.

Despite holding only a local office and being unknown outside California, in a poll on January 22, 1992, he tied with two well-known national politicians: Senator Tom Harkin of Iowa and the former governor of his home state, Jerry Brown.

According to Carole Florman, organizer of the Global Warming Leadership Forum in Tallahassee in February (in which Agran participated), "the audience was more enthusiastic about Larry Agran than about Bill Clinton".

Agran performed poorly in the New Hampshire primary, but did pick up modest support in later primaries as a protest candidate with appeal to those unhappy with the other candidates. He received three votes at the 1992 Democratic National Convention.

Agran was excluded from every television debate, along with some other minor candidates, such as Eugene McCarthy.

City Council, 2020

 * Tammy Kim – 43,744 (14.8%) (elected)
 * Mike Carroll – 38,615 (13.1%) (elected)
 * Larry Agran – 38,156 (12.9%) (elected)
 * Lauren Johnson-Norris – 37,931 (12.8%)
 * John Park – 32,521 (11.0%)
 * Carrie O'Malley – 27,440 (9.3%)
 * Mark Newgent – 15,894 (5.4%)
 * Diana Jiang – 14,837 (5.0%)
 * Laura Bratton – 10,305 (3.5%)
 * Dylan Green – 8,814 (3.0%)
 * Christina Dillard – 8,321 (2.8%)
 * Anshul Garg – 6,420 (2.2%)
 * Abigail Pole – 6,406 (2.2%)
 * Hai Yang Liang – 5,944 (2.0%)

City Council, 2014

 * Lynn Schott – 16,814 (22.9%) (elected)
 * Jeffrey Lalloway – 16,749 (22.8%) (elected)
 * Melissa Fox – 16,539 (22.5%)
 * Larry Agran – 14,403 (19.6%)
 * Evan Chemers – 8,966 (12.2%)

Mayor of Irvine, 2012

 * Steven S. Choi – 32,505 (45.7%) (elected)
 * Larry Agran – 28,741 (40.4%)
 * Katherine Daigle – 9,951 (13.9%)

Note: Larry Agran continued to serve on Irvine City Council as Councilmember through 2014

City Council, 2010

 * Larry Agran – 22,206 (23.6%) (elected)
 * Jeffrey Lalloway – 20,959 (22.3%) (elected)
 * Lynn Schott – 18,630 (19.8%)
 * Shiva Farivar – 17,657 (18.8%)
 * Chris Moore – 8,259 (8.8%)
 * Bijan Mazarji – 3,327 (3.5%)
 * Yunus Aksoy – 3,037 (3.2%)

City Council, 2008

 * Beth Krom – 36,924 (19.5%) (elected)
 * Steven S. Choi – 28,886 (15.3%) (elected)
 * Larry Agran – 28,157 (14.9%) (elected)
 * Margie Wakeham – 22,669 (12.0%)
 * Todd Gallinger – 22,423 (11.9%)
 * Patrick A. Rodgers – 22,093 (11.7%)
 * Eric Johnson – 11,022 (5.8%)
 * Bea Foster – 10,877 (5.8%)
 * Ruby Young – 3,697 (2.0%)
 * Paris Merriam – 2,354 (1.2%)

Note: 3rd runner up elected to a two-year term for purpose of filling vacancy created by Sukhee Kang’s election to Mayor

City Council, 2004

 * Larry Agran – 25,210 (16.9%) (elected)
 * Steven S. Choi – 25,052 (16.8%) (elected)
 * Sukhee Kang – 24,642 (16.5%)
 * Debbie Coven – 24,261 (16.2%)
 * Mike House – 22,561 (15.1%)
 * Greg Smith – 22,326 (14.9%)
 * Mohsen Alinaghian – 5,336 (3.6%)

Mayor of Irvine, 2002

 * Larry Agran – 19,886 (53.4%) (elected)
 * Mike House – 17,358 (46.6%)

Mayor of Irvine, 2000

 * Larry Agran – 34,905 (100.0%) (elected unopposed)

City Council, 1998

 * Larry Agran – 14,434 (22.4%) (elected)
 * Greg Smith – 13,004 (20.2%) (elected)
 * Ned E. Kassouf – 10,452 (16.3%)
 * Carolyn McInerney – 10,422 (16.2%)
 * George Michael Gallagher – 6,655 (10.3%)
 * Don Irvine – 4,662 (7.2%)
 * Jack Wu – 2,902 (4.5%)
 * Savvas Roditis – 1,776 (2.8%)

Mayor of Irvine, 1990

 * Sally Anne Sheridan – 14,256 (51.2%) (elected)
 * Larry Agran – 13,584 (48.8%)

Mayor of Irvine, 1988

 * Larry Agran – 15,651 (57.0%) (elected)
 * Barry J. Hammond – 8,707 (31.7%)
 * Hal Maloney – 3,111 (11.3%)

Note: first directly elected Mayor of Irvine

City Council, 1986

 * Larry Agran – 11,056 (27.9%) (elected)
 * Ed Dornan – 10,737 (27.1%) (elected)
 * Tom Jones – 5,513 (13.9%)
 * Hal Maloney – 5,221 (13.2%)
 * Jean Hobart – 2,822 (7.1%)
 * Mary Aileen Matheis – 1,543 (3.9%)
 * Gary Steven Bennett – 669 (1.7%)
 * Scott Wellman – 607 (1.5%)
 * Anthony R. Korba – 551 (1.4%)
 * Betsy Scherr – 551 (1.4%)
 * Clarence P. Becwar – 351 (0.9%)

City Council, 1988

 * Larry Agran – 8,696 (27.5%) (elected)
 * Barbara Wiener – 8,295 (26.2%) (elected)
 * John Nakaoka – 5,875 (18.6%)
 * Edward A. Dornan – 5,567 (17.6%)
 * Bill Pozzi – 2,083 (6.6%)
 * Marjorie Keiser – 1,142 (3.6%)

City Council, 1978

 * Larry Agran – 2,742 (22.7%) (elected)
 * Arthur W. Anthony – 2,423 (20.0%) (elected)
 * Ellen G. Freund – 1,885 (15.6%) (elected)
 * Robert L. “Bob” Moore – 1,859 (15.4%)
 * C. Larry Hoffman – 1,818 (15.0%)
 * Vivian Hall – 1,206 (10.0%)
 * David Warren – 61 (0.5%)
 * Jerry Shaw – 55 (0.5%)
 * Carol Effenberger – 49 (0.4%)

Note: Offices in Irvine are formally nonpartisan.

1992 Democratic National Convention (delegates)

 * Bill Clinton – 3,372 (80.27%)
 * Jerry Brown – 596 (14.19%)
 * Paul Tsongas – 209 (4.98%)
 * Robert P. Casey – 10 (0.24%)
 * Patricia Schroeder – 8 (0.19%)
 * Larry Agran – 3 (0.07%)
 * Ron Daniels – 1 (0.02%)
 * Al Gore – 1 (0.02%)
 * Joe Simonetta 1 (0.02%)

====1992 United States presidential election (Democratic primary) ====
 * Bill Clinton – 10,482,411 (52.01%)
 * Jerry Brown – 4,071,232 (20.20%)
 * Paul Tsongas – 3,656,010 (18.14%)
 * Unpledged – 750,873 (3.73%)
 * Bob Kerrey – 318,457 (1.58%)
 * Tom Harkin – 280,304 (1.39%)
 * Lyndon LaRouche – 154,599 (0.77%)
 * Eugene McCarthy – 108,678 (0.54%)
 * Charles Woods – 88,948 (0.44%)
 * Larry Agran – 58,611 (0.29%)
 * Ross Perot – 54,755 (0.27%)
 * Ralph Nader – 35,935 (0.18%)
 * Louis Stokes – 29,983 (0.15%)
 * Angus Wheeler McDonald – 9,900 (0.05%)
 * J. Louis McAlpine – 7,911 (0.04%)
 * George W. Benns – 7,887 (0.04%)
 * Rufus T. Higginbotham – 7,705 (0.04%)
 * Tom Howard Hawks – 7,434 (0.04%)
 * Stephen Bruke – 5,261 (0.03%)
 * Tom Laughlin – 5,202 (0.03%)
 * Tom Shiekman – 4,965 (0.03%)
 * Jeffrey F. Marsh – 2,445 (0.01%)
 * George Ballard – 2,067 (0.01%)
 * Ray Rollinson – 1,206 (0.01%)
 * Lenora Fulani – 402 (0.00%)
 * Douglas Wilder – 240 (0.00%)

Including write-in candidates.

title: Larry Agran


text:
Talk:Teradata

Request to update introduction
Hello again. I have a final (at least for now!) request for improving this Wikipedia article, which I am submitting on behalf of my employer. Currently the first sentence says, "Teradata Corporation is a provider of database-related products and services." Since the article has been updated based on above requests, I'd like to propose changing the first sentence to: "Teradata Corporation is a provider of database and analytics-related products and services." This more accurately describes the company. You have helped with several requests, so I'm wondering if you agree with this proposed change based on the improvements you've already made. Thanks again for your continued help. Dodds_Writer (Talk · Disclosure: Employee of Teradata) 22:15, 26 April 2018 (UTC)

Reply 26-APR-2018
✅ As one of the purposes in maintaining databases is for analysis of data stored within them, it stands to reason that analytics would be a normal and expected companion term for a company already responsible for database services, so I've added that word to the lead. Additionally, I would like to place a Wikilink for the word analytics, but there are several instances of it in Wikipedia. If you could take a look at this analytics disambiguation list and let me know which form of analytics would best be used for that Wikilink, I would appreciate it. Thank you! 0.70em 23:09, 26 April 2018 (UTC)

Merge proposal

 * Support merge (Feb 2017 proposal) in of Teradata Geospatial given a lack of independent notability . Klbrain (talk) 10:36, 4 August 2018 (UTC)
 * Addendum: similarly support merges for Teradata Parallel Transporter and Teradata Warehouse Miner. Klbrain (talk) 10:38, 4 August 2018 (UTC)

Enabling the reference to Aprimo to have its own wiki page
BeckieSch (talk) 16:17, 5 September 2018 (UTC)BeckieSch

The only existence of Aprimo on Wiki is on this Teradata page, but Teradata no longer owns Aprimo. It's an independent company. I'd like to remove the redirect and begin creation of a separate Aprimo page. How can I begin to do this? — Preceding unsigned comment added by BeckieSch (talk • contribs) 14:22, 5 September 2018 (UTC)

- I see you have helped with other edits to this page, can you help me with this? --BeckieSch (talk) 16:23, 5 September 2018 (UTC)

BeckieSch (talk) 16:20, 5 September 2018 (UTC)BeckieSch

New logo
https://www.google.com.pk/search?q=teradata+logo&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiw8fPXt4DeAhUClJAKHWfBBWsQ_AUIDigB&biw=1660&bih=860#imgrc=lRyxGpeSk9UhQM: — Preceding unsigned comment added by 141.206.231.10 (talk) 08:06, 12 October 2018 (UTC) Company changed the logo. — Preceding unsigned comment added by 141.206.231.10 (talk) 08:09, 12 October 2018 (UTC)
 * ✓ Completed – New logo uploaded to Commons as File:Teradata logo 2018.png, and change made in the article infobox. Senator2029 “Talk” 08:56, 12 October 2018 (UTC)

title: Talk:Teradata


text:
Color gel

A color gel or color filter (Commonwealth spelling: colour gel or colour filter), also known as lighting gel or simply gel, is a transparent colored material that is used in theater, event production, photography, videography and cinematography to color light and for color correction. Modern gels are thin sheets of polycarbonate, polyester or other heat-resistant plastics, placed in front of a lighting fixture in the path of the beam.

Gels have a limited life, especially in saturated colors (lower light transmission) and shorter wavelength (blues). The color will fade or even melt, depending upon the energy absorption of the color, and the sheet will have to be replaced.

In permanent installations and some theatrical uses, colored glass filters or dichroic filters are used. The main drawbacks are additional expense and a more limited selection.

History
In Shakespearean-era theater, red wine was used in a glass container as a light filter. In later days, colored water or silk was used to filter light in the theater. Later, a gelatin base became the material of choice. Gelatin gel was available at least until 1979. The name gel has continued to be used to the present day. Gelatin-based color media had no melting point, and the color was cast in the media as opposed to being coated on the surface. It would, however, char at high temperatures and become brittle once heated, so that it could not be handled once used in the lighting instrument.

By 1945 more heat-tolerant and self-extinguishing acetate-based through-dyed materials were being manufactured (marketed as Chromoid then Cinemoid by Strand Electric). In the U.S., Roscolene (acetate) was developed to deal with higher output light sources. Though cheaper, the acetate filters eventually fell out of favor with professional organizations since they could not withstand the higher temperatures produced by the tungsten halogen lamps that came into widespread use in the late 1960s.

The acetate-based material was replaced by polycarbonates like Roscolar (mylar polycarbonate) and polyester-based filters. These materials have superior heat tolerance. Polyester having the highest melting point of 480 F.

Often a surface coating was applied on a transparent film. The first dyed polyester gels were introduced by Berkey Colortran in 1969 as Gelatran, the original deep-dyed polyester. The Gelatran process is still used today to produce GAMColor (100% of the line) and Roscolux (about 30% of the line). Other color manufacturers, such as Lee Filters and Apollo Design Technology, use a surface applied dye. (Roscolux is 70% polycarbonate and 30% deep-dyed polyester.)

Almost every color manufacturer today uses either polycarbonate or polyester to manufacture their gels. Even today's gels can burn out (to lighten in color starting in the center) easily, rendering them useless. As instrument design improves, it has become a selling point on many lights to have as little heat radiating from the front of the fixture as possible to prevent burn-through, and keep stage equipment and actors cooler.

In the 1930s, Strand Electric of London provided the first numbering system for their swatches and with their agents in New York and Sydney the numbering system went round the world. Remnants of this original filter color system exist in the color swatches of today (such as Deep Amber = No. 3; Primary Red = No. 6; Middle Rose = No. 10; Peacock Blue = No. 15; Primary Blue = No. 20; Primary Green = No. 39).

In the theater, gels are typically available in single 20 x sheets, which are then cut down to the appropriate size before use. The size originates from the gelatin days: it is the same as a standard baker's sheet, which was used to cast the sheets. In the film industry, gels are usually cut straight from rolls 24 or wide and 50 ft long, as the size required may vary from a single practical halogen spotlight in a ceiling to a whole window.

Colors
Similar colors may vary between different companies' formulations. For example, many have a color named "bastard amber", but the transmitted color spectrum may be different. For this reason it is often misleading to refer to gel colors by name. Even a familiar color name, like Steel Blue, transmits widely differing colored light in each manufacturer's line.

By necessity color gels are selected by specifying the manufacturer, line, color number, and name: Rosco Cinegel #3202 Full Blue CTB.

Apollo Design Technology uses a four digit number based on the visible spectrum to designate and locate specific color transmissions.

The GAMColor line from Rosco employs a three digit numbering system, organized by the wavelength of the principle color in the family, i.e.: Blues in the 800's with primary blue at 850 (though the manufacturer's numbers do not relate directly to any wavelength, transmission, or frequency). The same applies to Greens in the 600's, Reds in the 200's, etc.

Rosco's Roscolux line is currently the oldest major line of color media,. They started using only a two-digit numbering system, listing colors in no particular order. As the range demanded by designers increased and many more colors were offered in the 1970's and 1980's, two digits quickly proved inadequate. As a result the original scheme was overlayed by three-digit and eventually four-digit numbers in between the original two-digit colors in the line.

Manufacturers produce swatch books, which contain a small sample of each color, along with the color name and manufacturer's catalogue number. Many manufacturers also provide spectral analysis for each color and transmission values, expressed as a percentage of light allowed to pass through the filter from the light source. Swatch books enable designers and technicians to have a true representation of the manufacturers' range of colors.

Many designers choose a limited color palette for generic applications because it is financially and logistically difficult to have access to all colors for a single show.

There are also gels for color correction, such as CTB (color temperature blue) and CTO (color temperature orange). Color correction gels alter or correct the color temperature of a light to more closely match the color temperature of a film negative or the white balance of a digital imager. Specifically CTB, which is blue in appearance, will correct tungsten lights that typically have a color temperature in the range of 3,200 to 5,700 kelvins to more closely match the color temperature of "daylight" negative, which is usually around 5,400 K (nominal daylight). CTO, which is orange in appearance, will correct a "daylight"-balanced light source (such as many common HMI bulbs) to match the color temperature of tungsten negative, which is typically 3,200 K. There are "half" and "quarter" variations of the common color correction gels. It is common to use color correction gels for artistic purposes and not just for negative-to-lightsource correction.

Most ranges of gels also include non-colored media, such as a variety of diffusion and directional "silk" materials to produce special lighting effects. "Opal" for example is an opalescent or translucent diffusion filter.

It is common for a gel manufacturer to publish the transmission coefficient or even the spectral transmittance curve in the swatch book and catalogs. A low transmittance gel will produce relatively little light on stage, but will cast a much more vivid color than a high transmission gel, because the colorfulness of a light source is directly related to narrowness of its spectral linewidth. Conversely, the flatter its curve becomes, the closer the gel is to a neutral density filter.

title: Color gel


text:
Newspaper Rock State Historic Monument

Newspaper Rock State Historic Monument is a Utah state monument featuring a rock panel carved with one of the largest known collections of petroglyphs. It is located in San Juan County, along Utah State Route 211, 28 mi northwest of Monticello and 53 mi south of Moab.

It is along the relatively well-traveled access road into the Needles district of Canyonlands National Park, 12 mi from US 191 and 30 mi from the park boundary. The 200 sqft rock is a part of the vertical Wingate sandstone cliffs that enclose the upper end of Indian Creek Canyon, and is covered by hundreds of petroglyphs—one of the largest, best preserved and easily accessed groups in the Southwest. The petroglyphs feature a mixture of human, animal, material and abstract forms.

Newspaper Rock was designated a State Historical Monument in 1961, and was added to the National Register of Historic Places listings in San Juan County, Utah as Indian Creek State Park in 1976.

Petroglyphs
The first carvings at the Newspaper Rock site were made around 2,000 years ago, left by people from the Archaic, Anasazi, Fremont, Navajo, Anglo, and Pueblo cultures.

In Navajo, the rock is called "Tse' Hone'" which translates to a rock that tells a story. The petroglyphs were carved by Native Americans during both the prehistoric and historic periods. There are over 650 rock art designs. The drawings on the rock are of different animals, human figures, and symbols. These carvings include pictures of deer, buffalo, and pronghorn antelope. Some glyphs depict riders on horses, while other images depict past events like in a newspaper. While precisely dating the rock carvings has been difficult, repatination of surface minerals reveals their relative ages. The reason for the large concentration of the petroglyphs is unclear. One suggested explanation is that the rock was used as a place for communication through the petroglyphs between travelers.

The pictures at Newspaper Rock were inscribed into the dark coating on the rock, called desert varnish. Desert varnish is mainly made up (~70%) by clay materials, but gets its blackish color from iron and manganese oxide deposits that gradually form on exposed sandstone cliff faces owing to the action of rainfall and bacteria. The ancient artists produced the many types of figures and patterns by carefully chipping the coated rock surfaces with sharpened tools to remove the desert varnish and expose the lighter rock beneath. The older figures are themselves becoming darker in color as new varnish slowly develops.

Depiction of Polydactyly
Many of the petroglyphs appear to be depicting polydactyly, the condition of having an extra toe or finger. In other Puebloan sites, burial remains with bifid metatarsals have been found near petroglyphs depicting polydactyly, suggesting that the pictures factually represent a real physical abnormality. One team of anthropologists excavated 96 skeletons from the nearby site of Pueblo Bonito and found that 3.1% of the skeletons had an extra toe on the right foot. This is a significantly higher rate of polydactyly than is seen in current Native American populations. There was evidence towards those with six toes being buried with items associated with higher social status, like an ornate bracelet, and turquoise. Polydactyl is also considered a moderately heritable condition, with 30-35% of those displaying the distinction also having a close relative with polydactyl. This means that it may be possible to use polydactyl to reconstruct ancient Puebloan lineages.

title: Newspaper Rock State Historic Monument


text:
Gobo

Gobo may refer to:

Places

 * Gobō, Wakayama, a city located in Wakayama Prefecture, Japan
 * Gobō Station, a railway station in the city
 * Gobo, Cameroon, a commune in Cameroon

Plants

 * Gobō (Arctium lappa), a biennial plant
 * Gobo (burdock), the root of the burdock (Arctium), a popular food in Asia

Other definitions

 * Gobo (lighting), a template or pattern that controls the shape of the light from a projector or spotlight.
 * Gobo (recording), a movable acoustic isolation panel
 * Gobo Fraggle, a character in the television series Fraggle Rock
 * GoboLinux, a Linux distribution
 * Gobo, a character in Bambi, a Life in the Woods

title: Gobo


text:
Fredrikshald

Fredrikshald may refer to:

 * Fredrikshald Bay, Nunavut, Canada
 * Fredrikshald, Norway, former name of the town of Halden

title: Fredrikshald


text:
Grus

Grus can refer to

 * Grus (genus), a genus of birds in the crane family
 * Grus grus, the common crane
 * Grus (constellation), the constellation "Crane"
 * Grus (geology), an accumulation of angular, coarse-grained fragments (particles of sand and gravel) resulting from the granular disintegration of crystalline rocks

title: Grus


text:
GCT

GCT may refer to:

Medicine

 * Germ cell tumor
 * Giant-cell tumor of bone
 * Glucose challenge test
 * Granulosa cell tumor

Transport

 * Gauge Change Train, a Japanese train
 * Ghazipur City railway station, in Uttar Pradesh, India
 * Grand Canyon Bar 10 Airport, in Arizona, United States
 * Grand Central Terminal, in New York City
 * Great Coates railway station in England
 * Grimsby-Cleethorpes Transport, former municipal bus company of Grimsby and Cleethorpes, England
 * Gwinnett County Transit, in Georgia, United States

Other uses

 * Galapagos Conservation Trust, a British charity
 * Genetic coding technologies, a frequently advertised investment area
 * Geometric complexity theory
 * German Colonial Tovar dialect of German, spoken in Venezuela
 * Global Champions Tour, a show jumping series
 * Gloucester County Times, a daily newspaper in New Jersey
 * Government College of Technology (disambiguation)
 * Grand Chess Tour, an annual circuit of chess tournaments
 * Grande Cadence de Tir (GCT) 155mm, French self-propelled artillery vehicle
 * Green Card Test, used by the United States Internal Revenue Service
 * Green Crescent Trust, in Sindh, Pakistan
 * Greene County Tech School District, in Greene County, Arkansas, United States
 * Greenwood Community Theatre, in South Carolina, United States
 * GCT, a codon for the amino acid Alanine

title: GCT