Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases. Lunisolar calendars may require intercalations of both months; the solar or tropical year does not have a whole number of days, but a calendar year must have a whole number of days. The most common way to reconcile the two is to vary the number of days in the calendar year. In solar calendars, this is done by adding to a common year of 365 days, an extra day about every four years, causing a leap year to have 366 days; the Decree of Canopus, issued by the pharaoh Ptolemy III Euergetes of Ancient Egypt in 239 BCE, decreed a solar leap day system. In the Julian calendar, as well as in the Gregorian calendar, which improved upon it, intercalation is done by adding an extra day to February in each leap year. In the Julian calendar this was done every four years. In the Gregorian, years not 400 were exempted in order to improve accuracy.
Thus, 2000 was a leap year. Epagomenal days are days within a solar calendar. Five epagomenal days are included within every year, but a sixth epagomenal day is intercalated every four years in some; the Bahá'í calendar includes enough epagomenal days before the last month to ensure that the following year starts on the March equinox. These are known as the Ayyám-i-Há; the solar year does not have a whole number of lunar months, so a lunisolar calendar must have a variable number of months in a year. Regular years have 12 months, but embolismic years insert a 13th "intercalary" or "leap" or "embolismic" month every second or third year. Whether to insert an intercalary month in a given year may be determined using regular cycles such as the 19-year Metonic cycle or using calculations of lunar phases; the Buddhist calendar adds both an intercalary day and month on a regular cycle. The tabular Islamic calendar has 12 lunar months that alternate between 30 and 29 days every year, but an intercalary day is added to the last month of the year 11 times within a 30-year cycle.
Some historians linked the pre-Islamic practice of Nasi' to intercalation. The Solar Hijri calendar is based on solar calculations and is similar to the Gregorian calendar in its structure, hence the intercalation, with the exception that the year date starts with the Hegira; the International Earth Rotation and Reference Systems Service can insert or remove leap seconds from the last day of any month. These are sometimes described as intercalary. ISO 8601 includes a specification for a 52/53-week year. Any year that has 53 Thursdays has 53 weeks; the xiuhpōhualli system of the Aztec calendar had five intercalary days after the eighteenth and final month, the nēmontēmi, in which the people reflect on the past year and do fasting. Lunisolar calendar Egyptian and Ethiopian calendars Iranian calendar Islamic calendar Celtic calendar Thai lunar calendar Bengali calendar Igbo calendar World Calendar Intercalated Games
The 2011 Ulster Senior Football Championship was the 123rd installment of the annual Ulster Senior Football Championship held under the auspices of the Ulster GAA. It was won by Donegal, it was their first Ulster title since 1992. The winning Donegal team received the Anglo-Celt Cup, automatically advanced to the quarter-final stage of the 2011 All-Ireland Senior Football Championship. Donegal's semi-final defeat of Tyrone and Derry's semi-final defeat of Armagh brought about the end of a long period of dominance by these two counties. Armagh and Tyrone had shared the previous eleven Ulster senior titles between them in a run stretching back to 1999, it brought a first major trophy for Jim McGuinness's famed Donegal team, who would go on to consign the decade-long dominance of those two counties to history. Ulster GAA website
The order of battle of Australian forces during the Vietnam War consisted of a small group of military advisors from 1962, but grew to include an infantry battalion based in Bien Hoa in 1965. This force was replaced by a two- and three-battalion task force with supporting arms based at Nui Dat which operated in Phuoc Tuy Province between 1966–71, with logistic elements at Vung Tau. Airforce units committed consisted of transport aircraft, but were followed by helicopters and bombers, while naval forces included destroyers and transport vessels. With the size of Australian forces in Vietnam reaching a peak in early 1968, a drawdown commenced in late 1970, with the bulk withdrawn by early 1972; the last elements returned to Australia in 1973. In total, around 50,000 Australians served during the Vietnam War, including 42,437 members of the Australian Army, 3,310 from the Royal Australian Navy, 4,443 from the Royal Australian Air Force, with casualties including 519 killed and 2,348 wounded. Australian Army Training Team Vietnam – Saigon Australian Army Force Vietnam – Saigon 709 Sig Tp 1st Battalion, Royal Australian Regiment Battle Group – Bien Hoa 1st APC Troop – M113 Armoured Personnel Carriers 105th Field Battery, Royal Australian Artillery 3rd Field Troop 161st Reconnaissance Flight – Bell Souix Light Observation Helicopters and Cessna 180s – Bien Hoa Australian Logistic Support Company – Bien Hoa Australian Force Vietnam – Saigon 145 Sig Sqn 110 Sig Sqn 1st Australian Task Force – Nui Dat Infantry: Royal Australian Regiment:1st Battalion, Royal Australian Regiment 2nd Battalion, Royal Australian Regiment 3rd Battalion, Royal Australian Regiment 4th Battalion, Royal Australian Regiment 5th Battalion, Royal Australian Regiment 6th Battalion, Royal Australian Regiment 7th Battalion, Royal Australian Regiment 8th Battalion, Royal Australian Regiment 9th Battalion, Royal Australian Regiment Special Air Service Regiment:1st Squadron 2nd Squadron 3rd Squadron Armour:1st APC Squadron – M113 Armoured Personnel Carriers A Squadron, 3rd Cavalry Regiment – M113 Armoured Personnel Carriers B Squadron, 3rd Cavalry Regiment – M113 Armoured Personnel Carriers A Squadron, 1st Armoured Regiment – Centurion tanks B Squadron, 1st Armoured Regiment – Centurion tanks C Squadron, 1st Armoured Regiment – Centurion tanks Detachment, 1st Forward Delivery Troop Artillery:1st Field Regiment, Royal Australian Artillery 101st Field Battery, Royal Australian Artillery 103rd Field Battery, Royal Australian Artillery 105th Field Battery, Royal Australian Artillery 4th Field Regiment, Royal Australian Artillery 106th Field Battery, Royal Australian Artillery 107th Field Battery, Royal Australian Artillery 108th Field Battery, Royal Australian Artillery 12th Field Regiment, Royal Australian Artillery **** A Field Battery, Royal Australian Artillery 102nd Field Battery, Royal Australian Artillery 104th Field Battery, Royal Australian Artillery 131st Divisional Locating Battery, Royal Australian Artillery Engineers:1st Field Squadron 21st Engineer Support Troop Aviation:161st Reconnaissance Flight – Bell Souix Light Observation Helicopters, Cessna 180s, Cessna Bird Dog and Pilatus Porters – Vung Tau / Nui Dat Intelligence:Detachment, 1st Divisional Intelligence Unit 1st Psychological Operations Unit Signals:103 Sig Sqn 104 Sig Sqn 1st Australian Logistics Support Group – Vung Tau 1st Australian Civil Affairs Unit – Nui Dat and Vung Tau Transport:RAAF Transport Flight Vietnam – DHC-4 Caribous – Butterworth / Vung Tau No. 35 Squadron RAAF – DHC-4 Caribous – Vung Tau Helicopter:No. 9 Squadron RAAF – UH-1 Iroquois – Vung Tau Bomber:No. 2 Squadron RAAF – English Electric Canberras – Phan Ran Other units:No. 1 Operational Support Unit No. 5 Airfield Construction Squadron RAAF Destroyers:HMAS Brisbane HMAS Perth (September 1967 – A